/*
** Add a single new WhereTerm entry to the WhereClause object pWC.
** The new WhereTerm object is constructed from Expr p and with wtFlags.
** The index in pWC->a[] of the new WhereTerm is returned on success.
** 0 is returned if the new WhereTerm could not be added due to a memory
** allocation error. The memory allocation failure will be recorded in
** the db->mallocFailed flag so that higher-level functions can detect it.
**
** This routine will increase the size of the pWC->a[] array as necessary.
**
** If the wtFlags argument includes TERM_DYNAMIC, then responsibility
** for freeing the expression p is assumed by the WhereClause object pWC.
** This is true even if this routine fails to allocate a new WhereTerm.
**
** WARNING: This routine might reallocate the space used to store
** WhereTerms. All pointers to WhereTerms should be invalidated after
** calling this routine. Such pointers may be reinitialized by referencing
** the pWC->a[] array.
*/
static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){
WhereTerm *pTerm;
int idx;
testcase( wtFlags & TERM_VIRTUAL );
if( pWC->nTerm>=pWC->nSlot ){
WhereTerm *pOld = pWC->a;
sqlite3 *db = pWC->pWInfo->pParse->db;
pWC->a = sqlite3DbMallocRaw(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
if( pWC->a==0 ){
if( wtFlags & TERM_DYNAMIC ){
sqlite3ExprDelete(db, p);
}
pWC->a = pOld;
return 0;
}
memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
if( pOld!=pWC->aStatic ){
sqlite3DbFree(db, pOld);
}
pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
memset(&pWC->a[pWC->nTerm], 0, sizeof(pWC->a[0])*(pWC->nSlot-pWC->nTerm));
}
pTerm = &pWC->a[idx = pWC->nTerm++];
if( p && ExprHasProperty(p, EP_Unlikely) ){
pTerm->truthProb = sqlite3LogEst(p->iTable) - 270;
}else{
pTerm->truthProb = 1;
}
pTerm->pExpr = sqlite3ExprSkipCollate(p);
pTerm->wtFlags = wtFlags;
pTerm->pWC = pWC;
pTerm->iParent = -1;
return idx;
}
int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
int rc;
if( pExpr==0 ) return WRC_Continue;
testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
testcase( ExprHasProperty(pExpr, EP_Reduced) );
rc = pWalker->xExprCallback(pWalker, pExpr);
if( rc==WRC_Continue
&& !ExprHasAnyProperty(pExpr,EP_TokenOnly) ){
if( sqlite3WalkExpr(pWalker, pExpr->pLeft) ) return WRC_Abort;
if( sqlite3WalkExpr(pWalker, pExpr->pRight) ) return WRC_Abort;
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
}else{
if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
}
}
return rc & WRC_Abort;
}
/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
** If the result set column is a simple column reference, then this routine
** makes an exact copy. But for any other kind of expression, this
** routine make a copy of the result set column as the argument to the
** TK_AS operator. The TK_AS operator causes the expression to be
** evaluated just once and then reused for each alias.
**
** The reason for suppressing the TK_AS term when the expression is a simple
** column reference is so that the column reference will be recognized as
** usable by indices within the WHERE clause processing logic.
**
** Hack: The TK_AS operator is inhibited if zType[0]=='G'. This means
** that in a GROUP BY clause, the expression is evaluated twice. Hence:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x
**
** Is equivalent to:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set. We might fix this someday. Or
** then again, we might not...
*/
static void resolveAlias(
Parse *pParse, /* Parsing context */
ExprList *pEList, /* A result set */
int iCol, /* A column in the result set. 0..pEList->nExpr-1 */
Expr *pExpr, /* Transform this into an alias to the result set */
const char *zType /* "GROUP" or "ORDER" or "" */
){
Expr *pOrig; /* The iCol-th column of the result set */
Expr *pDup; /* Copy of pOrig */
sqlite3 *db; /* The database connection */
assert( iCol>=0 && iCol<pEList->nExpr );
pOrig = pEList->a[iCol].pExpr;
assert( pOrig!=0 );
assert( pOrig->flags & EP_Resolved );
db = pParse->db;
if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
pDup = sqlite3ExprDup(db, pOrig, 0);
pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
if( pDup==0 ) return;
if( pEList->a[iCol].iAlias==0 ){
pEList->a[iCol].iAlias = (u16)(++pParse->nAlias);
}
pDup->iTable = pEList->a[iCol].iAlias;
}else if( ExprHasProperty(pOrig, EP_IntValue) || pOrig->u.zToken==0 ){
pDup = sqlite3ExprDup(db, pOrig, 0);
if( pDup==0 ) return;
}else{
char *zToken = pOrig->u.zToken;
assert( zToken!=0 );
pOrig->u.zToken = 0;
pDup = sqlite3ExprDup(db, pOrig, 0);
pOrig->u.zToken = zToken;
if( pDup==0 ) return;
assert( (pDup->flags & (EP_Reduced|EP_TokenOnly))==0 );
pDup->flags2 |= EP2_MallocedToken;
pDup->u.zToken = sqlite3DbStrDup(db, zToken);
}
if( pExpr->flags & EP_ExpCollate ){
pDup->pColl = pExpr->pColl;
pDup->flags |= EP_ExpCollate;
}
/* Before calling sqlite3ExprDelete(), set the EP_Static flag. This
** prevents ExprDelete() from deleting the Expr structure itself,
** allowing it to be repopulated by the memcpy() on the following line.
*/
ExprSetProperty(pExpr, EP_Static);
sqlite3ExprDelete(db, pExpr);
memcpy(pExpr, pDup, sizeof(*pExpr));
sqlite3DbFree(db, pDup);
}
/*
** Turn the pExpr expression into an alias for the iCol-th column of the
** result set in pEList.
**
** If the result set column is a simple column reference, then this routine
** makes an exact copy. But for any other kind of expression, this
** routine make a copy of the result set column as the argument to the
** TK_AS operator. The TK_AS operator causes the expression to be
** evaluated just once and then reused for each alias.
**
** The reason for suppressing the TK_AS term when the expression is a simple
** column reference is so that the column reference will be recognized as
** usable by indices within the WHERE clause processing logic.
**
** The TK_AS operator is inhibited if zType[0]=='G'. This means
** that in a GROUP BY clause, the expression is evaluated twice. Hence:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x
**
** Is equivalent to:
**
** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set. On the other hand Standard SQL does
** not allow the GROUP BY clause to contain references to result-set columns.
** So this should never come up in well-formed queries.
**
** If the reference is followed by a COLLATE operator, then make sure
** the COLLATE operator is preserved. For example:
**
** SELECT a+b, c+d FROM t1 ORDER BY 1 COLLATE nocase;
**
** Should be transformed into:
**
** SELECT a+b, c+d FROM t1 ORDER BY (a+b) COLLATE nocase;
**
** The nSubquery parameter specifies how many levels of subquery the
** alias is removed from the original expression. The usually value is
** zero but it might be more if the alias is contained within a subquery
** of the original expression. The Expr.op2 field of TK_AGG_FUNCTION
** structures must be increased by the nSubquery amount.
*/
static void resolveAlias(
Parse *pParse, /* Parsing context */
ExprList *pEList, /* A result set */
int iCol, /* A column in the result set. 0..pEList->nExpr-1 */
Expr *pExpr, /* Transform this into an alias to the result set */
const char *zType, /* "GROUP" or "ORDER" or "" */
int nSubquery /* Number of subqueries that the label is moving */
){
Expr *pOrig; /* The iCol-th column of the result set */
Expr *pDup; /* Copy of pOrig */
sqlite3 *db; /* The database connection */
assert( iCol>=0 && iCol<pEList->nExpr );
pOrig = pEList->a[iCol].pExpr;
assert( pOrig!=0 );
assert( pOrig->flags & EP_Resolved );
db = pParse->db;
pDup = sqlite3ExprDup(db, pOrig, 0);
if( pDup==0 ) return;
if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
incrAggFunctionDepth(pDup, nSubquery);
pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
if( pDup==0 ) return;
ExprSetProperty(pDup, EP_Skip);
if( pEList->a[iCol].u.x.iAlias==0 ){
pEList->a[iCol].u.x.iAlias = (u16)(++pParse->nAlias);
}
pDup->iTable = pEList->a[iCol].u.x.iAlias;
}
if( pExpr->op==TK_COLLATE ){
pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
}
/* Before calling sqlite3ExprDelete(), set the EP_Static flag. This
** prevents ExprDelete() from deleting the Expr structure itself,
** allowing it to be repopulated by the memcpy() on the following line.
** The pExpr->u.zToken might point into memory that will be freed by the
** sqlite3DbFree(db, pDup) on the last line of this block, so be sure to
** make a copy of the token before doing the sqlite3DbFree().
*/
ExprSetProperty(pExpr, EP_Static);
sqlite3ExprDelete(db, pExpr);
memcpy(pExpr, pDup, sizeof(*pExpr));
if( !ExprHasProperty(pExpr, EP_IntValue) && pExpr->u.zToken!=0 ){
assert( (pExpr->flags & (EP_Reduced|EP_TokenOnly))==0 );
pExpr->u.zToken = sqlite3DbStrDup(db, pExpr->u.zToken);
pExpr->flags |= EP_MemToken;
}
sqlite3DbFree(db, pDup);
}
/*
** These routines walk (recursively) an expression tree and generate
** a bitmask indicating which tables are used in that expression
** tree.
*/
Bitmask sqlite3WhereExprUsage(WhereMaskSet *pMaskSet, Expr *p){
Bitmask mask = 0;
if( p==0 ) return 0;
if( p->op==TK_COLUMN ){
mask = sqlite3WhereGetMask(pMaskSet, p->iTable);
return mask;
}
mask = sqlite3WhereExprUsage(pMaskSet, p->pRight);
mask |= sqlite3WhereExprUsage(pMaskSet, p->pLeft);
if( ExprHasProperty(p, EP_xIsSelect) ){
mask |= exprSelectUsage(pMaskSet, p->x.pSelect);
}else{
mask |= sqlite3WhereExprListUsage(pMaskSet, p->x.pList);
}
return mask;
}
int sqlite3FixExpr(
DbFixer *pFix, /* Context of the fixation */
Expr *pExpr /* The expression to be fixed to one database */
){
while( pExpr ){
if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ) break;
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
if( sqlite3FixSelect(pFix, pExpr->x.pSelect) ) return 1;
}else{
if( sqlite3FixExprList(pFix, pExpr->x.pList) ) return 1;
}
if( sqlite3FixExpr(pFix, pExpr->pRight) ){
return 1;
}
pExpr = pExpr->pLeft;
}
return 0;
}
int sqlite3FixExpr(
DbFixer *pFix,
Expr *pExpr
){
while( pExpr ){
if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ) break;
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
if( sqlite3FixSelect(pFix, pExpr->x.pSelect) ) return 1;
}else{
if( sqlite3FixExprList(pFix, pExpr->x.pList) ) return 1;
}
if( sqlite3FixExpr(pFix, pExpr->pRight) ){
return 1;
}
pExpr = pExpr->pLeft;
}
return 0;
}
/*
** This routine walks an expression tree and resolves references to
** table columns and result-set columns. At the same time, do error
** checking on function usage and set a flag if any aggregate functions
** are seen.
**
** To resolve table columns references we look for nodes (or subtrees) of the
** form X.Y.Z or Y.Z or just Z where
**
** X: The name of a database. Ex: "main" or "temp" or
** the symbolic name assigned to an ATTACH-ed database.
**
** Y: The name of a table in a FROM clause. Or in a trigger
** one of the special names "old" or "new".
**
** Z: The name of a column in table Y.
**
** The node at the root of the subtree is modified as follows:
**
** Expr.op Changed to TK_COLUMN
** Expr.pTab Points to the Table object for X.Y
** Expr.iColumn The column index in X.Y. -1 for the rowid.
** Expr.iTable The VDBE cursor number for X.Y
**
**
** To resolve result-set references, look for expression nodes of the
** form Z (with no X and Y prefix) where the Z matches the right-hand
** size of an AS clause in the result-set of a SELECT. The Z expression
** is replaced by a copy of the left-hand side of the result-set expression.
** Table-name and function resolution occurs on the substituted expression
** tree. For example, in:
**
** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
**
** The "x" term of the order by is replaced by "a+b" to render:
**
** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
**
** Function calls are checked to make sure that the function is
** defined and that the correct number of arguments are specified.
** If the function is an aggregate function, then the NC_HasAgg flag is
** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
** If an expression contains aggregate functions then the EP_Agg
** property on the expression is set.
**
** An error message is left in pParse if anything is amiss. The number
** if errors is returned.
*/
int sqlite3ResolveExprNames(
NameContext *pNC, /* Namespace to resolve expressions in. */
Expr *pExpr /* The expression to be analyzed. */
){
u8 savedHasAgg;
Walker w;
if( pExpr==0 ) return 0;
#if SQLITE_MAX_EXPR_DEPTH>0
{
Parse *pParse = pNC->pParse;
if( sqlite3ExprCheckHeight(pParse, pExpr->nHeight+pNC->pParse->nHeight) ){
return 1;
}
pParse->nHeight += pExpr->nHeight;
}
#endif
savedHasAgg = pNC->ncFlags & NC_HasAgg;
pNC->ncFlags &= ~NC_HasAgg;
memset(&w, 0, sizeof(w));
w.xExprCallback = resolveExprStep;
w.xSelectCallback = resolveSelectStep;
w.pParse = pNC->pParse;
w.u.pNC = pNC;
sqlite3WalkExpr(&w, pExpr);
#if SQLITE_MAX_EXPR_DEPTH>0
pNC->pParse->nHeight -= pExpr->nHeight;
#endif
if( pNC->nErr>0 || w.pParse->nErr>0 ){
ExprSetProperty(pExpr, EP_Error);
}
if( pNC->ncFlags & NC_HasAgg ){
ExprSetProperty(pExpr, EP_Agg);
}else if( savedHasAgg ){
pNC->ncFlags |= NC_HasAgg;
}
return ExprHasProperty(pExpr, EP_Error);
}
/*
** We already know that pExpr is a binary operator where both operands are
** column references. This routine checks to see if pExpr is an equivalence
** relation:
** 1. The SQLITE_Transitive optimization must be enabled
** 2. Must be either an == or an IS operator
** 3. Not originating in the ON clause of an OUTER JOIN
** 4. The affinities of A and B must be compatible
** 5a. Both operands use the same collating sequence OR
** 5b. The overall collating sequence is BINARY
** If this routine returns TRUE, that means that the RHS can be substituted
** for the LHS anyplace else in the WHERE clause where the LHS column occurs.
** This is an optimization. No harm comes from returning 0. But if 1 is
** returned when it should not be, then incorrect answers might result.
*/
static int termIsEquivalence(Parse *pParse, Expr *pExpr){
char aff1, aff2;
CollSeq *pColl;
const char *zColl1, *zColl2;
if( !OptimizationEnabled(pParse->db, SQLITE_Transitive) ) return 0;
if( pExpr->op!=TK_EQ && pExpr->op!=TK_IS ) return 0;
if( ExprHasProperty(pExpr, EP_FromJoin) ) return 0;
aff1 = sqlite3ExprAffinity(pExpr->pLeft);
aff2 = sqlite3ExprAffinity(pExpr->pRight);
if( aff1!=aff2
&& (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2))
){
return 0;
}
pColl = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft, pExpr->pRight);
if( pColl==0 || sqlite3StrICmp(pColl->zName, "BINARY")==0 ) return 1;
pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
/* Since pLeft and pRight are both a column references, their collating
** sequence should always be defined. */
zColl1 = ALWAYS(pColl) ? pColl->zName : 0;
pColl = sqlite3ExprCollSeq(pParse, pExpr->pRight);
zColl2 = ALWAYS(pColl) ? pColl->zName : 0;
return sqlite3StrICmp(zColl1, zColl2)==0;
}
/*
** Create a new sqlite3_value object, containing the value of pExpr.
**
** This only works for very simple expressions that consist of one constant
** token (i.e. "5", "5.1", "'a string'"). If the expression can
** be converted directly into a value, then the value is allocated and
** a pointer written to *ppVal. The caller is responsible for deallocating
** the value by passing it to sqlite3ValueFree() later on. If the expression
** cannot be converted to a value, then *ppVal is set to NULL.
*/
int sqlite3ValueFromExpr(
sqlite3 *db, /* The database connection */
Expr *pExpr, /* The expression to evaluate */
u8 enc, /* Encoding to use */
u8 affinity, /* Affinity to use */
sqlite3_value **ppVal /* Write the new value here */
){
int op;
char *zVal = 0;
sqlite3_value *pVal = 0;
int negInt = 1;
const char *zNeg = "";
if( !pExpr ){
*ppVal = 0;
return SQLITE_OK;
}
op = pExpr->op;
/* op can only be TK_REGISTER if we have compiled with SQLITE_ENABLE_STAT3.
** The ifdef here is to enable us to achieve 100% branch test coverage even
** when SQLITE_ENABLE_STAT3 is omitted.
*/
#ifdef SQLITE_ENABLE_STAT3
if( op==TK_REGISTER ) op = pExpr->op2;
#else
if( NEVER(op==TK_REGISTER) ) op = pExpr->op2;
#endif
/* Handle negative integers in a single step. This is needed in the
** case when the value is -9223372036854775808.
*/
if( op==TK_UMINUS
&& (pExpr->pLeft->op==TK_INTEGER || pExpr->pLeft->op==TK_FLOAT) ){
pExpr = pExpr->pLeft;
op = pExpr->op;
negInt = -1;
zNeg = "-";
}
if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
pVal = sqlite3ValueNew(db);
if( pVal==0 ) goto no_mem;
if( ExprHasProperty(pExpr, EP_IntValue) ){
sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
}else{
zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
if( zVal==0 ) goto no_mem;
sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
if( op==TK_FLOAT ) pVal->type = SQLITE_FLOAT;
}
if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
}else{
sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
}
if( pVal->flags & (MEM_Int|MEM_Real) ) pVal->flags &= ~MEM_Str;
if( enc!=SQLITE_UTF8 ){
sqlite3VdbeChangeEncoding(pVal, enc);
}
}else if( op==TK_UMINUS ) {
/* This branch happens for multiple negative signs. Ex: -(-5) */
if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
sqlite3VdbeMemNumerify(pVal);
if( pVal->u.i==SMALLEST_INT64 ){
pVal->flags &= MEM_Int;
pVal->flags |= MEM_Real;
pVal->r = (double)LARGEST_INT64;
}else{
pVal->u.i = -pVal->u.i;
}
pVal->r = -pVal->r;
sqlite3ValueApplyAffinity(pVal, affinity, enc);
}
}else if( op==TK_NULL ){
pVal = sqlite3ValueNew(db);
if( pVal==0 ) goto no_mem;
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
else if( op==TK_BLOB ){
int nVal;
assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
assert( pExpr->u.zToken[1]=='\'' );
pVal = sqlite3ValueNew(db);
if( !pVal ) goto no_mem;
zVal = &pExpr->u.zToken[2];
nVal = sqlite3Strlen30(zVal)-1;
assert( zVal[nVal]=='\'' );
sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
0, SQLITE_DYNAMIC);
}
#endif
if( pVal ){
sqlite3VdbeMemStoreType(pVal);
}
*ppVal = pVal;
return SQLITE_OK;
no_mem:
db->mallocFailed = 1;
sqlite3DbFree(db, zVal);
sqlite3ValueFree(pVal);
*ppVal = 0;
return SQLITE_NOMEM;
}
/*
** Resolve names in the SELECT statement p and all of its descendents.
*/
static int resolveSelectStep(Walker *pWalker, Select *p){
NameContext *pOuterNC; /* Context that contains this SELECT */
NameContext sNC; /* Name context of this SELECT */
int isCompound; /* True if p is a compound select */
int nCompound; /* Number of compound terms processed so far */
Parse *pParse; /* Parsing context */
ExprList *pEList; /* Result set expression list */
int i; /* Loop counter */
ExprList *pGroupBy; /* The GROUP BY clause */
Select *pLeftmost; /* Left-most of SELECT of a compound */
sqlite3 *db; /* Database connection */
assert( p!=0 );
if( p->selFlags & SF_Resolved ){
return WRC_Prune;
}
pOuterNC = pWalker->u.pNC;
pParse = pWalker->pParse;
db = pParse->db;
/* Normally sqlite3SelectExpand() will be called first and will have
** already expanded this SELECT. However, if this is a subquery within
** an expression, sqlite3ResolveExprNames() will be called without a
** prior call to sqlite3SelectExpand(). When that happens, let
** sqlite3SelectPrep() do all of the processing for this SELECT.
** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and
** this routine in the correct order.
*/
if( (p->selFlags & SF_Expanded)==0 ){
sqlite3SelectPrep(pParse, p, pOuterNC);
return (pParse->nErr || db->mallocFailed) ? WRC_Abort : WRC_Prune;
}
isCompound = p->pPrior!=0;
nCompound = 0;
pLeftmost = p;
while( p ){
assert( (p->selFlags & SF_Expanded)!=0 );
assert( (p->selFlags & SF_Resolved)==0 );
p->selFlags |= SF_Resolved;
/* Resolve the expressions in the LIMIT and OFFSET clauses. These
** are not allowed to refer to any names, so pass an empty NameContext.
*/
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pParse;
if( sqlite3ResolveExprNames(&sNC, p->pLimit) ||
sqlite3ResolveExprNames(&sNC, p->pOffset) ){
return WRC_Abort;
}
/* Set up the local name-context to pass to sqlite3ResolveExprNames() to
** resolve the result-set expression list.
*/
sNC.allowAgg = 1;
sNC.pSrcList = p->pSrc;
sNC.pNext = pOuterNC;
/* Resolve names in the result set. */
pEList = p->pEList;
assert( pEList!=0 );
for(i=0; i<pEList->nExpr; i++){
Expr *pX = pEList->a[i].pExpr;
if( sqlite3ResolveExprNames(&sNC, pX) ){
return WRC_Abort;
}
}
/* Recursively resolve names in all subqueries
*/
for(i=0; i<p->pSrc->nSrc; i++){
struct SrcList_item *pItem = &p->pSrc->a[i];
if( pItem->pSelect ){
const char *zSavedContext = pParse->zAuthContext;
if( pItem->zName ) pParse->zAuthContext = pItem->zName;
sqlite3ResolveSelectNames(pParse, pItem->pSelect, pOuterNC);
pParse->zAuthContext = zSavedContext;
if( pParse->nErr || db->mallocFailed ) return WRC_Abort;
}
}
/* If there are no aggregate functions in the result-set, and no GROUP BY
** expression, do not allow aggregates in any of the other expressions.
*/
assert( (p->selFlags & SF_Aggregate)==0 );
pGroupBy = p->pGroupBy;
if( pGroupBy || sNC.hasAgg ){
p->selFlags |= SF_Aggregate;
}else{
sNC.allowAgg = 0;
}
/* If a HAVING clause is present, then there must be a GROUP BY clause.
*/
if( p->pHaving && !pGroupBy ){
sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
return WRC_Abort;
}
/* Add the expression list to the name-context before parsing the
** other expressions in the SELECT statement. This is so that
** expressions in the WHERE clause (etc.) can refer to expressions by
** aliases in the result set.
**
** Minor point: If this is the case, then the expression will be
** re-evaluated for each reference to it.
*/
sNC.pEList = p->pEList;
if( sqlite3ResolveExprNames(&sNC, p->pWhere) ||
sqlite3ResolveExprNames(&sNC, p->pHaving)
){
return WRC_Abort;
}
/* The ORDER BY and GROUP BY clauses may not refer to terms in
** outer queries
*/
sNC.pNext = 0;
sNC.allowAgg = 1;
/* Process the ORDER BY clause for singleton SELECT statements.
** The ORDER BY clause for compounds SELECT statements is handled
** below, after all of the result-sets for all of the elements of
** the compound have been resolved.
*/
if( !isCompound && resolveOrderGroupBy(&sNC, p, p->pOrderBy, "ORDER") ){
return WRC_Abort;
}
if( db->mallocFailed ){
return WRC_Abort;
}
/* Resolve the GROUP BY clause. At the same time, make sure
** the GROUP BY clause does not contain aggregate functions.
*/
if( pGroupBy ){
struct ExprList_item *pItem;
if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){
return WRC_Abort;
}
for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
"the GROUP BY clause");
return WRC_Abort;
}
}
}
/* Advance to the next term of the compound
*/
p = p->pPrior;
nCompound++;
}
/* Resolve the ORDER BY on a compound SELECT after all terms of
** the compound have been resolved.
*/
if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){
return WRC_Abort;
}
return WRC_Prune;
}
/*
** Generate a human-readable explanation of an expression tree.
*/
void sqlite3TreeViewExpr(TreeView *pView, const Expr *pExpr, u8 moreToFollow){
const char *zBinOp = 0; /* Binary operator */
const char *zUniOp = 0; /* Unary operator */
char zFlgs[30];
pView = sqlite3TreeViewPush(pView, moreToFollow);
if( pExpr==0 ){
sqlite3TreeViewLine(pView, "nil");
sqlite3TreeViewPop(pView);
return;
}
if( pExpr->flags ){
sqlite3_snprintf(sizeof(zFlgs),zFlgs," flags=0x%x",pExpr->flags);
}else{
zFlgs[0] = 0;
}
switch( pExpr->op ){
case TK_AGG_COLUMN: {
sqlite3TreeViewLine(pView, "AGG{%d:%d}%s",
pExpr->iTable, pExpr->iColumn, zFlgs);
break;
}
case TK_COLUMN: {
if( pExpr->iTable<0 ){
/* This only happens when coding check constraints */
sqlite3TreeViewLine(pView, "COLUMN(%d)%s", pExpr->iColumn, zFlgs);
}else{
sqlite3TreeViewLine(pView, "{%d:%d}%s",
pExpr->iTable, pExpr->iColumn, zFlgs);
}
break;
}
case TK_INTEGER: {
if( pExpr->flags & EP_IntValue ){
sqlite3TreeViewLine(pView, "%d", pExpr->u.iValue);
}else{
sqlite3TreeViewLine(pView, "%s", pExpr->u.zToken);
}
break;
}
#ifndef SQLITE_OMIT_FLOATING_POINT
case TK_FLOAT: {
sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
break;
}
#endif
case TK_STRING: {
sqlite3TreeViewLine(pView,"%Q", pExpr->u.zToken);
break;
}
case TK_NULL: {
sqlite3TreeViewLine(pView,"NULL");
break;
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
case TK_BLOB: {
sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
break;
}
#endif
case TK_VARIABLE: {
sqlite3TreeViewLine(pView,"VARIABLE(%s,%d)",
pExpr->u.zToken, pExpr->iColumn);
break;
}
case TK_REGISTER: {
sqlite3TreeViewLine(pView,"REGISTER(%d)", pExpr->iTable);
break;
}
case TK_AS: {
sqlite3TreeViewLine(pView,"AS %Q", pExpr->u.zToken);
sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
break;
}
case TK_ID: {
sqlite3TreeViewLine(pView,"ID \"%w\"", pExpr->u.zToken);
break;
}
#ifndef SQLITE_OMIT_CAST
case TK_CAST: {
/* Expressions of the form: CAST(pLeft AS token) */
sqlite3TreeViewLine(pView,"CAST %Q", pExpr->u.zToken);
sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
break;
}
#endif /* SQLITE_OMIT_CAST */
case TK_LT: zBinOp = "LT"; break;
case TK_LE: zBinOp = "LE"; break;
case TK_GT: zBinOp = "GT"; break;
case TK_GE: zBinOp = "GE"; break;
case TK_NE: zBinOp = "NE"; break;
case TK_EQ: zBinOp = "EQ"; break;
case TK_IS: zBinOp = "IS"; break;
case TK_ISNOT: zBinOp = "ISNOT"; break;
case TK_AND: zBinOp = "AND"; break;
case TK_OR: zBinOp = "OR"; break;
case TK_PLUS: zBinOp = "ADD"; break;
case TK_STAR: zBinOp = "MUL"; break;
case TK_MINUS: zBinOp = "SUB"; break;
case TK_REM: zBinOp = "REM"; break;
case TK_BITAND: zBinOp = "BITAND"; break;
case TK_BITOR: zBinOp = "BITOR"; break;
case TK_SLASH: zBinOp = "DIV"; break;
case TK_LSHIFT: zBinOp = "LSHIFT"; break;
case TK_RSHIFT: zBinOp = "RSHIFT"; break;
case TK_CONCAT: zBinOp = "CONCAT"; break;
case TK_DOT: zBinOp = "DOT"; break;
case TK_UMINUS: zUniOp = "UMINUS"; break;
case TK_UPLUS: zUniOp = "UPLUS"; break;
case TK_BITNOT: zUniOp = "BITNOT"; break;
case TK_NOT: zUniOp = "NOT"; break;
case TK_ISNULL: zUniOp = "ISNULL"; break;
case TK_NOTNULL: zUniOp = "NOTNULL"; break;
case TK_COLLATE: {
sqlite3TreeViewLine(pView, "COLLATE %Q", pExpr->u.zToken);
sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
break;
}
case TK_AGG_FUNCTION:
case TK_FUNCTION: {
ExprList *pFarg; /* List of function arguments */
if( ExprHasProperty(pExpr, EP_TokenOnly) ){
pFarg = 0;
}else{
pFarg = pExpr->x.pList;
}
if( pExpr->op==TK_AGG_FUNCTION ){
sqlite3TreeViewLine(pView, "AGG_FUNCTION%d %Q",
pExpr->op2, pExpr->u.zToken);
}else{
sqlite3TreeViewLine(pView, "FUNCTION %Q", pExpr->u.zToken);
}
if( pFarg ){
sqlite3TreeViewExprList(pView, pFarg, 0, 0);
}
break;
}
#ifndef SQLITE_OMIT_SUBQUERY
case TK_EXISTS: {
sqlite3TreeViewLine(pView, "EXISTS-expr");
sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
break;
}
case TK_SELECT: {
sqlite3TreeViewLine(pView, "SELECT-expr");
sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
break;
}
case TK_IN: {
sqlite3TreeViewLine(pView, "IN");
sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
sqlite3TreeViewSelect(pView, pExpr->x.pSelect, 0);
}else{
sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
}
break;
}
#endif /* SQLITE_OMIT_SUBQUERY */
/*
** x BETWEEN y AND z
**
** This is equivalent to
**
** x>=y AND x<=z
**
** X is stored in pExpr->pLeft.
** Y is stored in pExpr->pList->a[0].pExpr.
** Z is stored in pExpr->pList->a[1].pExpr.
*/
case TK_BETWEEN: {
Expr *pX = pExpr->pLeft;
Expr *pY = pExpr->x.pList->a[0].pExpr;
Expr *pZ = pExpr->x.pList->a[1].pExpr;
sqlite3TreeViewLine(pView, "BETWEEN");
sqlite3TreeViewExpr(pView, pX, 1);
sqlite3TreeViewExpr(pView, pY, 1);
sqlite3TreeViewExpr(pView, pZ, 0);
break;
}
case TK_TRIGGER: {
/* If the opcode is TK_TRIGGER, then the expression is a reference
** to a column in the new.* or old.* pseudo-tables available to
** trigger programs. In this case Expr.iTable is set to 1 for the
** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
** is set to the column of the pseudo-table to read, or to -1 to
** read the rowid field.
*/
sqlite3TreeViewLine(pView, "%s(%d)",
pExpr->iTable ? "NEW" : "OLD", pExpr->iColumn);
break;
}
case TK_CASE: {
sqlite3TreeViewLine(pView, "CASE");
sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
sqlite3TreeViewExprList(pView, pExpr->x.pList, 0, 0);
break;
}
#ifndef SQLITE_OMIT_TRIGGER
case TK_RAISE: {
const char *zType = "unk";
switch( pExpr->affinity ){
case OE_Rollback: zType = "rollback"; break;
case OE_Abort: zType = "abort"; break;
case OE_Fail: zType = "fail"; break;
case OE_Ignore: zType = "ignore"; break;
}
sqlite3TreeViewLine(pView, "RAISE %s(%Q)", zType, pExpr->u.zToken);
break;
}
#endif
default: {
sqlite3TreeViewLine(pView, "op=%d", pExpr->op);
break;
}
}
if( zBinOp ){
sqlite3TreeViewLine(pView, "%s%s", zBinOp, zFlgs);
sqlite3TreeViewExpr(pView, pExpr->pLeft, 1);
sqlite3TreeViewExpr(pView, pExpr->pRight, 0);
}else if( zUniOp ){
sqlite3TreeViewLine(pView, "%s%s", zUniOp, zFlgs);
sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);
}
sqlite3TreeViewPop(pView);
}
/*
** This routine is callback for sqlite3WalkExpr().
**
** Resolve symbolic names into TK_COLUMN operators for the current
** node in the expression tree. Return 0 to continue the search down
** the tree or 2 to abort the tree walk.
**
** This routine also does error checking and name resolution for
** function names. The operator for aggregate functions is changed
** to TK_AGG_FUNCTION.
*/
static int resolveExprStep(Walker *pWalker, Expr *pExpr){
NameContext *pNC;
Parse *pParse;
pNC = pWalker->u.pNC;
assert( pNC!=0 );
pParse = pNC->pParse;
assert( pParse==pWalker->pParse );
if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return WRC_Prune;
ExprSetProperty(pExpr, EP_Resolved);
#ifndef NDEBUG
if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
SrcList *pSrcList = pNC->pSrcList;
int i;
for(i=0; i<pNC->pSrcList->nSrc; i++){
assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
}
}
#endif
switch( pExpr->op ){
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
/* The special operator TK_ROW means use the rowid for the first
** column in the FROM clause. This is used by the LIMIT and ORDER BY
** clause processing on UPDATE and DELETE statements.
*/
case TK_ROW: {
SrcList *pSrcList = pNC->pSrcList;
struct SrcList_item *pItem;
assert( pSrcList && pSrcList->nSrc==1 );
pItem = pSrcList->a;
pExpr->op = TK_COLUMN;
pExpr->pTab = pItem->pTab;
pExpr->iTable = pItem->iCursor;
pExpr->iColumn = -1;
pExpr->affinity = SQLITE_AFF_INTEGER;
break;
}
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) */
/* A lone identifier is the name of a column.
*/
case TK_ID: {
return lookupName(pParse, 0, 0, pExpr->u.zToken, pNC, pExpr);
}
/* A table name and column name: ID.ID
** Or a database, table and column: ID.ID.ID
*/
case TK_DOT: {
const char *zColumn;
const char *zTable;
const char *zDb;
Expr *pRight;
/* if( pSrcList==0 ) break; */
pRight = pExpr->pRight;
if( pRight->op==TK_ID ){
zDb = 0;
zTable = pExpr->pLeft->u.zToken;
zColumn = pRight->u.zToken;
}else{
assert( pRight->op==TK_DOT );
zDb = pExpr->pLeft->u.zToken;
zTable = pRight->pLeft->u.zToken;
zColumn = pRight->pRight->u.zToken;
}
return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
}
/* Resolve function names
*/
case TK_CONST_FUNC:
case TK_FUNCTION: {
ExprList *pList = pExpr->x.pList; /* The argument list */
int n = pList ? pList->nExpr : 0; /* Number of arguments */
int no_such_func = 0; /* True if no such function exists */
int wrong_num_args = 0; /* True if wrong number of arguments */
int is_agg = 0; /* True if is an aggregate function */
int auth; /* Authorization to use the function */
int nId; /* Number of characters in function name */
const char *zId; /* The function name. */
FuncDef *pDef; /* Information about the function */
u8 enc = ENC(pParse->db); /* The database encoding */
testcase( pExpr->op==TK_CONST_FUNC );
assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
zId = pExpr->u.zToken;
nId = sqlite3Strlen30(zId);
pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
if( pDef==0 ){
pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0);
if( pDef==0 ){
no_such_func = 1;
}else{
wrong_num_args = 1;
}
}else{
is_agg = pDef->xFunc==0;
}
#ifndef SQLITE_OMIT_AUTHORIZATION
if( pDef ){
auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0);
if( auth!=SQLITE_OK ){
if( auth==SQLITE_DENY ){
sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
pDef->zName);
pNC->nErr++;
}
pExpr->op = TK_NULL;
return WRC_Prune;
}
}
#endif
if( is_agg && !pNC->allowAgg ){
sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
pNC->nErr++;
is_agg = 0;
}else if( no_such_func ){
sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
pNC->nErr++;
}else if( wrong_num_args ){
sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
nId, zId);
pNC->nErr++;
}
if( is_agg ){
pExpr->op = TK_AGG_FUNCTION;
pNC->hasAgg = 1;
}
if( is_agg ) pNC->allowAgg = 0;
sqlite3WalkExprList(pWalker, pList);
if( is_agg ) pNC->allowAgg = 1;
/* FIX ME: Compute pExpr->affinity based on the expected return
** type of the function
*/
return WRC_Prune;
}
#ifndef SQLITE_OMIT_SUBQUERY
case TK_SELECT:
case TK_EXISTS: testcase( pExpr->op==TK_EXISTS );
#endif
case TK_IN: {
testcase( pExpr->op==TK_IN );
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
int nRef = pNC->nRef;
#ifndef SQLITE_OMIT_CHECK
if( pNC->isCheck ){
sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints");
}
#endif
sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
assert( pNC->nRef>=nRef );
if( nRef!=pNC->nRef ){
ExprSetProperty(pExpr, EP_VarSelect);
}
}
break;
}
#ifndef SQLITE_OMIT_CHECK
case TK_VARIABLE: {
if( pNC->isCheck ){
sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints");
}
break;
}
#endif
}
return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue;
}
/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr
** expression node refer back to that source column. The following changes
** are made to pExpr:
**
** pExpr->iDb Set the index in db->aDb[] of the database X
** (even if X is implied).
** pExpr->iTable Set to the cursor number for the table obtained
** from pSrcList.
** pExpr->pTab Points to the Table structure of X.Y (even if
** X and/or Y are implied.)
** pExpr->iColumn Set to the column number within the table.
** pExpr->op Set to TK_COLUMN.
** pExpr->pLeft Any expression this points to is deleted
** pExpr->pRight Any expression this points to is deleted.
**
** The zDb variable is the name of the database (the "X"). This value may be
** NULL meaning that name is of the form Y.Z or Z. Any available database
** can be used. The zTable variable is the name of the table (the "Y"). This
** value can be NULL if zDb is also NULL. If zTable is NULL it
** means that the form of the name is Z and that columns from any table
** can be used.
**
** If the name cannot be resolved unambiguously, leave an error message
** in pParse and return WRC_Abort. Return WRC_Prune on success.
*/
static int lookupName(
Parse *pParse, /* The parsing context */
const char *zDb, /* Name of the database containing table, or NULL */
const char *zTab, /* Name of table containing column, or NULL */
const char *zCol, /* Name of the column. */
NameContext *pNC, /* The name context used to resolve the name */
Expr *pExpr /* Make this EXPR node point to the selected column */
){
int i, j; /* Loop counters */
int cnt = 0; /* Number of matching column names */
int cntTab = 0; /* Number of matching table names */
sqlite3 *db = pParse->db; /* The database connection */
struct SrcList_item *pItem; /* Use for looping over pSrcList items */
struct SrcList_item *pMatch = 0; /* The matching pSrcList item */
NameContext *pTopNC = pNC; /* First namecontext in the list */
Schema *pSchema = 0; /* Schema of the expression */
int isTrigger = 0;
assert( pNC ); /* the name context cannot be NULL. */
assert( zCol ); /* The Z in X.Y.Z cannot be NULL */
assert( ~ExprHasAnyProperty(pExpr, EP_TokenOnly|EP_Reduced) );
/* Initialize the node to no-match */
pExpr->iTable = -1;
pExpr->pTab = 0;
ExprSetIrreducible(pExpr);
/* Start at the inner-most context and move outward until a match is found */
while( pNC && cnt==0 ){
ExprList *pEList;
SrcList *pSrcList = pNC->pSrcList;
if( pSrcList ){
for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
Table *pTab;
int iDb;
Column *pCol;
pTab = pItem->pTab;
assert( pTab!=0 && pTab->zName!=0 );
iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
assert( pTab->nCol>0 );
if( zTab ){
if( pItem->zAlias ){
char *zTabName = pItem->zAlias;
if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue;
}else{
char *zTabName = pTab->zName;
if( NEVER(zTabName==0) || sqlite3StrICmp(zTabName, zTab)!=0 ){
continue;
}
if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){
continue;
}
}
}
if( 0==(cntTab++) ){
pExpr->iTable = pItem->iCursor;
pExpr->pTab = pTab;
pSchema = pTab->pSchema;
pMatch = pItem;
}
for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
IdList *pUsing;
cnt++;
pExpr->iTable = pItem->iCursor;
pExpr->pTab = pTab;
pMatch = pItem;
pSchema = pTab->pSchema;
/* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
if( i<pSrcList->nSrc-1 ){
if( pItem[1].jointype & JT_NATURAL ){
/* If this match occurred in the left table of a natural join,
** then skip the right table to avoid a duplicate match */
pItem++;
i++;
}else if( (pUsing = pItem[1].pUsing)!=0 ){
/* If this match occurs on a column that is in the USING clause
** of a join, skip the search of the right table of the join
** to avoid a duplicate match there. */
int k;
for(k=0; k<pUsing->nId; k++){
if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){
pItem++;
i++;
break;
}
}
}
}
break;
}
}
}
}
#ifndef SQLITE_OMIT_TRIGGER
/* If we have not already resolved the name, then maybe
** it is a new.* or old.* trigger argument reference
*/
if( zDb==0 && zTab!=0 && cnt==0 && pParse->pTriggerTab!=0 ){
int op = pParse->eTriggerOp;
Table *pTab = 0;
assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
if( op!=TK_DELETE && sqlite3StrICmp("new",zTab) == 0 ){
pExpr->iTable = 1;
pTab = pParse->pTriggerTab;
}else if( op!=TK_INSERT && sqlite3StrICmp("old",zTab)==0 ){
pExpr->iTable = 0;
pTab = pParse->pTriggerTab;
}
if( pTab ){
int iCol;
pSchema = pTab->pSchema;
cntTab++;
for(iCol=0; iCol<pTab->nCol; iCol++){
Column *pCol = &pTab->aCol[iCol];
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
if( iCol==pTab->iPKey ){
iCol = -1;
}
break;
}
}
if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) ){
iCol = -1; /* IMP: R-44911-55124 */
}
if( iCol<pTab->nCol ){
cnt++;
if( iCol<0 ){
pExpr->affinity = SQLITE_AFF_INTEGER;
}else if( pExpr->iTable==0 ){
testcase( iCol==31 );
testcase( iCol==32 );
pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
}else{
testcase( iCol==31 );
testcase( iCol==32 );
pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
}
pExpr->iColumn = (i16)iCol;
pExpr->pTab = pTab;
isTrigger = 1;
}
}
}
#endif /* !defined(SQLITE_OMIT_TRIGGER) */
/*
** Perhaps the name is a reference to the ROWID
*/
if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){
cnt = 1;
pExpr->iColumn = -1; /* IMP: R-44911-55124 */
pExpr->affinity = SQLITE_AFF_INTEGER;
}
/*
** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
** might refer to an result-set alias. This happens, for example, when
** we are resolving names in the WHERE clause of the following command:
**
** SELECT a+b AS x FROM table WHERE x<10;
**
** In cases like this, replace pExpr with a copy of the expression that
** forms the result set entry ("a+b" in the example) and return immediately.
** Note that the expression in the result set should have already been
** resolved by the time the WHERE clause is resolved.
*/
if( cnt==0 && (pEList = pNC->pEList)!=0 && zTab==0 ){
for(j=0; j<pEList->nExpr; j++){
char *zAs = pEList->a[j].zName;
if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
Expr *pOrig;
assert( pExpr->pLeft==0 && pExpr->pRight==0 );
assert( pExpr->x.pList==0 );
assert( pExpr->x.pSelect==0 );
pOrig = pEList->a[j].pExpr;
if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){
sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
return WRC_Abort;
}
resolveAlias(pParse, pEList, j, pExpr, "");
cnt = 1;
pMatch = 0;
assert( zTab==0 && zDb==0 );
goto lookupname_end;
}
}
}
/* Advance to the next name context. The loop will exit when either
** we have a match (cnt>0) or when we run out of name contexts.
*/
if( cnt==0 ){
pNC = pNC->pNext;
}
}
/*
** If X and Y are NULL (in other words if only the column name Z is
** supplied) and the value of Z is enclosed in double-quotes, then
** Z is a string literal if it doesn't match any column names. In that
** case, we need to return right away and not make any changes to
** pExpr.
**
** Because no reference was made to outer contexts, the pNC->nRef
** fields are not changed in any context.
*/
if( cnt==0 && zTab==0 && ExprHasProperty(pExpr,EP_DblQuoted) ){
pExpr->op = TK_STRING;
pExpr->pTab = 0;
return WRC_Prune;
}
/*
** cnt==0 means there was not match. cnt>1 means there were two or
** more matches. Either way, we have an error.
*/
if( cnt!=1 ){
const char *zErr;
zErr = cnt==0 ? "no such column" : "ambiguous column name";
if( zDb ){
sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
}else if( zTab ){
sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
}else{
sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
}
pTopNC->nErr++;
}
/* If a column from a table in pSrcList is referenced, then record
** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes
** bit 0 to be set. Column 1 sets bit 1. And so forth. If the
** column number is greater than the number of bits in the bitmask
** then set the high-order bit of the bitmask.
*/
if( pExpr->iColumn>=0 && pMatch!=0 ){
int n = pExpr->iColumn;
testcase( n==BMS-1 );
if( n>=BMS ){
n = BMS-1;
}
assert( pMatch->iCursor==pExpr->iTable );
pMatch->colUsed |= ((Bitmask)1)<<n;
}
/* Clean up and return
*/
sqlite3ExprDelete(db, pExpr->pLeft);
pExpr->pLeft = 0;
sqlite3ExprDelete(db, pExpr->pRight);
pExpr->pRight = 0;
pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
lookupname_end:
if( cnt==1 ){
assert( pNC!=0 );
sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
/* Increment the nRef value on all name contexts from TopNC up to
** the point where the name matched. */
for(;;){
assert( pTopNC!=0 );
pTopNC->nRef++;
if( pTopNC==pNC ) break;
pTopNC = pTopNC->pNext;
}
return WRC_Prune;
} else {
return WRC_Abort;
}
}
/*
** The input to this routine is an WhereTerm structure with only the
** "pExpr" field filled in. The job of this routine is to analyze the
** subexpression and populate all the other fields of the WhereTerm
** structure.
**
** If the expression is of the form "<expr> <op> X" it gets commuted
** to the standard form of "X <op> <expr>".
**
** If the expression is of the form "X <op> Y" where both X and Y are
** columns, then the original expression is unchanged and a new virtual
** term of the form "Y <op> X" is added to the WHERE clause and
** analyzed separately. The original term is marked with TERM_COPIED
** and the new term is marked with TERM_DYNAMIC (because it's pExpr
** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it
** is a commuted copy of a prior term.) The original term has nChild=1
** and the copy has idxParent set to the index of the original term.
*/
static void exprAnalyze(
SrcList *pSrc, /* the FROM clause */
WhereClause *pWC, /* the WHERE clause */
int idxTerm /* Index of the term to be analyzed */
){
WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
WhereTerm *pTerm; /* The term to be analyzed */
WhereMaskSet *pMaskSet; /* Set of table index masks */
Expr *pExpr; /* The expression to be analyzed */
Bitmask prereqLeft; /* Prerequesites of the pExpr->pLeft */
Bitmask prereqAll; /* Prerequesites of pExpr */
Bitmask extraRight = 0; /* Extra dependencies on LEFT JOIN */
Expr *pStr1 = 0; /* RHS of LIKE/GLOB operator */
int isComplete = 0; /* RHS of LIKE/GLOB ends with wildcard */
int noCase = 0; /* uppercase equivalent to lowercase */
int op; /* Top-level operator. pExpr->op */
Parse *pParse = pWInfo->pParse; /* Parsing context */
sqlite3 *db = pParse->db; /* Database connection */
if( db->mallocFailed ){
return;
}
pTerm = &pWC->a[idxTerm];
pMaskSet = &pWInfo->sMaskSet;
pExpr = pTerm->pExpr;
assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft);
op = pExpr->op;
if( op==TK_IN ){
assert( pExpr->pRight==0 );
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect);
}else{
pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList);
}
}else if( op==TK_ISNULL ){
pTerm->prereqRight = 0;
}else{
pTerm->prereqRight = sqlite3WhereExprUsage(pMaskSet, pExpr->pRight);
}
prereqAll = sqlite3WhereExprUsage(pMaskSet, pExpr);
if( ExprHasProperty(pExpr, EP_FromJoin) ){
Bitmask x = sqlite3WhereGetMask(pMaskSet, pExpr->iRightJoinTable);
prereqAll |= x;
extraRight = x-1; /* ON clause terms may not be used with an index
** on left table of a LEFT JOIN. Ticket #3015 */
}
pTerm->prereqAll = prereqAll;
pTerm->leftCursor = -1;
pTerm->iParent = -1;
pTerm->eOperator = 0;
if( allowedOp(op) ){
Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft);
Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight);
u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
if( pLeft->op==TK_COLUMN ){
pTerm->leftCursor = pLeft->iTable;
pTerm->u.leftColumn = pLeft->iColumn;
pTerm->eOperator = operatorMask(op) & opMask;
}
if( op==TK_IS ) pTerm->wtFlags |= TERM_IS;
if( pRight && pRight->op==TK_COLUMN ){
WhereTerm *pNew;
Expr *pDup;
u16 eExtraOp = 0; /* Extra bits for pNew->eOperator */
if( pTerm->leftCursor>=0 ){
int idxNew;
pDup = sqlite3ExprDup(db, pExpr, 0);
if( db->mallocFailed ){
sqlite3ExprDelete(db, pDup);
return;
}
idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
if( idxNew==0 ) return;
pNew = &pWC->a[idxNew];
markTermAsChild(pWC, idxNew, idxTerm);
if( op==TK_IS ) pNew->wtFlags |= TERM_IS;
pTerm = &pWC->a[idxTerm];
pTerm->wtFlags |= TERM_COPIED;
if( termIsEquivalence(pParse, pDup) ){
pTerm->eOperator |= WO_EQUIV;
eExtraOp = WO_EQUIV;
}
}else{
pDup = pExpr;
pNew = pTerm;
}
exprCommute(pParse, pDup);
pLeft = sqlite3ExprSkipCollate(pDup->pLeft);
pNew->leftCursor = pLeft->iTable;
pNew->u.leftColumn = pLeft->iColumn;
testcase( (prereqLeft | extraRight) != prereqLeft );
pNew->prereqRight = prereqLeft | extraRight;
pNew->prereqAll = prereqAll;
pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask;
}
}
#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION
/* If a term is the BETWEEN operator, create two new virtual terms
** that define the range that the BETWEEN implements. For example:
**
** a BETWEEN b AND c
**
** is converted into:
**
** (a BETWEEN b AND c) AND (a>=b) AND (a<=c)
**
** The two new terms are added onto the end of the WhereClause object.
** The new terms are "dynamic" and are children of the original BETWEEN
** term. That means that if the BETWEEN term is coded, the children are
** skipped. Or, if the children are satisfied by an index, the original
** BETWEEN term is skipped.
*/
else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){
ExprList *pList = pExpr->x.pList;
int i;
static const u8 ops[] = {TK_GE, TK_LE};
assert( pList!=0 );
assert( pList->nExpr==2 );
for(i=0; i<2; i++){
Expr *pNewExpr;
int idxNew;
pNewExpr = sqlite3PExpr(pParse, ops[i],
sqlite3ExprDup(db, pExpr->pLeft, 0),
sqlite3ExprDup(db, pList->a[i].pExpr, 0), 0);
transferJoinMarkings(pNewExpr, pExpr);
idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
testcase( idxNew==0 );
exprAnalyze(pSrc, pWC, idxNew);
pTerm = &pWC->a[idxTerm];
markTermAsChild(pWC, idxNew, idxTerm);
}
}
#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */
#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
/* Analyze a term that is composed of two or more subterms connected by
** an OR operator.
*/
else if( pExpr->op==TK_OR ){
assert( pWC->op==TK_AND );
exprAnalyzeOrTerm(pSrc, pWC, idxTerm);
pTerm = &pWC->a[idxTerm];
}
#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
/* Add constraints to reduce the search space on a LIKE or GLOB
** operator.
**
** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints
**
** x>='ABC' AND x<'abd' AND x LIKE 'aBc%'
**
** The last character of the prefix "abc" is incremented to form the
** termination condition "abd". If case is not significant (the default
** for LIKE) then the lower-bound is made all uppercase and the upper-
** bound is made all lowercase so that the bounds also work when comparing
** BLOBs.
*/
if( pWC->op==TK_AND
&& isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase)
){
Expr *pLeft; /* LHS of LIKE/GLOB operator */
Expr *pStr2; /* Copy of pStr1 - RHS of LIKE/GLOB operator */
Expr *pNewExpr1;
Expr *pNewExpr2;
int idxNew1;
int idxNew2;
const char *zCollSeqName; /* Name of collating sequence */
const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC;
pLeft = pExpr->x.pList->a[1].pExpr;
pStr2 = sqlite3ExprDup(db, pStr1, 0);
/* Convert the lower bound to upper-case and the upper bound to
** lower-case (upper-case is less than lower-case in ASCII) so that
** the range constraints also work for BLOBs
*/
if( noCase && !pParse->db->mallocFailed ){
int i;
char c;
pTerm->wtFlags |= TERM_LIKE;
for(i=0; (c = pStr1->u.zToken[i])!=0; i++){
pStr1->u.zToken[i] = sqlite3Toupper(c);
pStr2->u.zToken[i] = sqlite3Tolower(c);
}
}
if( !db->mallocFailed ){
u8 c, *pC; /* Last character before the first wildcard */
pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1];
c = *pC;
if( noCase ){
/* The point is to increment the last character before the first
** wildcard. But if we increment '@', that will push it into the
** alphabetic range where case conversions will mess up the
** inequality. To avoid this, make sure to also run the full
** LIKE on all candidate expressions by clearing the isComplete flag
*/
if( c=='A'-1 ) isComplete = 0;
c = sqlite3UpperToLower[c];
}
*pC = c + 1;
}
zCollSeqName = noCase ? "NOCASE" : "BINARY";
pNewExpr1 = sqlite3ExprDup(db, pLeft, 0);
pNewExpr1 = sqlite3PExpr(pParse, TK_GE,
sqlite3ExprAddCollateString(pParse,pNewExpr1,zCollSeqName),
pStr1, 0);
transferJoinMarkings(pNewExpr1, pExpr);
idxNew1 = whereClauseInsert(pWC, pNewExpr1, wtFlags);
testcase( idxNew1==0 );
exprAnalyze(pSrc, pWC, idxNew1);
pNewExpr2 = sqlite3ExprDup(db, pLeft, 0);
pNewExpr2 = sqlite3PExpr(pParse, TK_LT,
sqlite3ExprAddCollateString(pParse,pNewExpr2,zCollSeqName),
pStr2, 0);
transferJoinMarkings(pNewExpr2, pExpr);
idxNew2 = whereClauseInsert(pWC, pNewExpr2, wtFlags);
testcase( idxNew2==0 );
exprAnalyze(pSrc, pWC, idxNew2);
pTerm = &pWC->a[idxTerm];
if( isComplete ){
markTermAsChild(pWC, idxNew1, idxTerm);
markTermAsChild(pWC, idxNew2, idxTerm);
}
}
#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Add a WO_MATCH auxiliary term to the constraint set if the
** current expression is of the form: column MATCH expr.
** This information is used by the xBestIndex methods of
** virtual tables. The native query optimizer does not attempt
** to do anything with MATCH functions.
*/
if( isMatchOfColumn(pExpr) ){
int idxNew;
Expr *pRight, *pLeft;
WhereTerm *pNewTerm;
Bitmask prereqColumn, prereqExpr;
pRight = pExpr->x.pList->a[0].pExpr;
pLeft = pExpr->x.pList->a[1].pExpr;
prereqExpr = sqlite3WhereExprUsage(pMaskSet, pRight);
prereqColumn = sqlite3WhereExprUsage(pMaskSet, pLeft);
if( (prereqExpr & prereqColumn)==0 ){
Expr *pNewExpr;
pNewExpr = sqlite3PExpr(pParse, TK_MATCH,
0, sqlite3ExprDup(db, pRight, 0), 0);
idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC);
testcase( idxNew==0 );
pNewTerm = &pWC->a[idxNew];
pNewTerm->prereqRight = prereqExpr;
pNewTerm->leftCursor = pLeft->iTable;
pNewTerm->u.leftColumn = pLeft->iColumn;
pNewTerm->eOperator = WO_MATCH;
markTermAsChild(pWC, idxNew, idxTerm);
pTerm = &pWC->a[idxTerm];
pTerm->wtFlags |= TERM_COPIED;
pNewTerm->prereqAll = pTerm->prereqAll;
}
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
/* When sqlite_stat3 histogram data is available an operator of the
** form "x IS NOT NULL" can sometimes be evaluated more efficiently
** as "x>NULL" if x is not an INTEGER PRIMARY KEY. So construct a
** virtual term of that form.
**
** Note that the virtual term must be tagged with TERM_VNULL.
*/
if( pExpr->op==TK_NOTNULL
&& pExpr->pLeft->op==TK_COLUMN
&& pExpr->pLeft->iColumn>=0
&& OptimizationEnabled(db, SQLITE_Stat34)
){
Expr *pNewExpr;
Expr *pLeft = pExpr->pLeft;
int idxNew;
WhereTerm *pNewTerm;
pNewExpr = sqlite3PExpr(pParse, TK_GT,
sqlite3ExprDup(db, pLeft, 0),
sqlite3PExpr(pParse, TK_NULL, 0, 0, 0), 0);
idxNew = whereClauseInsert(pWC, pNewExpr,
TERM_VIRTUAL|TERM_DYNAMIC|TERM_VNULL);
if( idxNew ){
pNewTerm = &pWC->a[idxNew];
pNewTerm->prereqRight = 0;
pNewTerm->leftCursor = pLeft->iTable;
pNewTerm->u.leftColumn = pLeft->iColumn;
pNewTerm->eOperator = WO_GT;
markTermAsChild(pWC, idxNew, idxTerm);
pTerm = &pWC->a[idxTerm];
pTerm->wtFlags |= TERM_COPIED;
pNewTerm->prereqAll = pTerm->prereqAll;
}
}
#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */
/* Prevent ON clause terms of a LEFT JOIN from being used to drive
** an index for tables to the left of the join.
*/
pTerm->prereqRight |= extraRight;
}
/*
** Analyze a term that consists of two or more OR-connected
** subterms. So in:
**
** ... WHERE (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13)
** ^^^^^^^^^^^^^^^^^^^^
**
** This routine analyzes terms such as the middle term in the above example.
** A WhereOrTerm object is computed and attached to the term under
** analysis, regardless of the outcome of the analysis. Hence:
**
** WhereTerm.wtFlags |= TERM_ORINFO
** WhereTerm.u.pOrInfo = a dynamically allocated WhereOrTerm object
**
** The term being analyzed must have two or more of OR-connected subterms.
** A single subterm might be a set of AND-connected sub-subterms.
** Examples of terms under analysis:
**
** (A) t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5
** (B) x=expr1 OR expr2=x OR x=expr3
** (C) t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
** (D) x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
** (E) (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
** (F) x>A OR (x=A AND y>=B)
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C and
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression. In other words, if the term
** being analyzed is:
**
** x = expr1 OR expr2 = x OR x = expr3
**
** then create a new virtual term like this:
**
** x IN (expr1,expr2,expr3)
**
** CASE 2:
**
** If there are exactly two disjuncts and one side has x>A and the other side
** has x=A (for the same x and A) then add a new virtual conjunct term to the
** WHERE clause of the form "x>=A". Example:
**
** x>A OR (x=A AND y>B) adds: x>=A
**
** The added conjunct can sometimes be helpful in query planning.
**
** CASE 3:
**
** If all subterms are indexable by a single table T, then set
**
** WhereTerm.eOperator = WO_OR
** WhereTerm.u.pOrInfo->indexable |= the cursor number for table T
**
** A subterm is "indexable" if it is of the form
** "T.C <op> <expr>" where C is any column of table T and
** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN".
** A subterm is also indexable if it is an AND of two or more
** subsubterms at least one of which is indexable. Indexable AND
** subterms have their eOperator set to WO_AND and they have
** u.pAndInfo set to a dynamically allocated WhereAndTerm object.
**
** From another point of view, "indexable" means that the subterm could
** potentially be used with an index if an appropriate index exists.
** This analysis does not consider whether or not the index exists; that
** is decided elsewhere. This analysis only looks at whether subterms
** appropriate for indexing exist.
**
** All examples A through E above satisfy case 3. But if a term
** also satisfies case 1 (such as B) we know that the optimizer will
** always prefer case 1, so in that case we pretend that case 3 is not
** satisfied.
**
** It might be the case that multiple tables are indexable. For example,
** (E) above is indexable on tables P, Q, and R.
**
** Terms that satisfy case 3 are candidates for lookup by using
** separate indices to find rowids for each subterm and composing
** the union of all rowids using a RowSet object. This is similar
** to "bitmap indices" in other database engines.
**
** OTHERWISE:
**
** If none of cases 1, 2, or 3 apply, then leave the eOperator set to
** zero. This term is not useful for search.
*/
static void exprAnalyzeOrTerm(
SrcList *pSrc, /* the FROM clause */
WhereClause *pWC, /* the complete WHERE clause */
int idxTerm /* Index of the OR-term to be analyzed */
){
WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
Parse *pParse = pWInfo->pParse; /* Parser context */
sqlite3 *db = pParse->db; /* Database connection */
WhereTerm *pTerm = &pWC->a[idxTerm]; /* The term to be analyzed */
Expr *pExpr = pTerm->pExpr; /* The expression of the term */
int i; /* Loop counters */
WhereClause *pOrWc; /* Breakup of pTerm into subterms */
WhereTerm *pOrTerm; /* A Sub-term within the pOrWc */
WhereOrInfo *pOrInfo; /* Additional information associated with pTerm */
Bitmask chngToIN; /* Tables that might satisfy case 1 */
Bitmask indexable; /* Tables that are indexable, satisfying case 2 */
/*
** Break the OR clause into its separate subterms. The subterms are
** stored in a WhereClause structure containing within the WhereOrInfo
** object that is attached to the original OR clause term.
*/
assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
assert( pExpr->op==TK_OR );
pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo));
if( pOrInfo==0 ) return;
pTerm->wtFlags |= TERM_ORINFO;
pOrWc = &pOrInfo->wc;
sqlite3WhereClauseInit(pOrWc, pWInfo);
sqlite3WhereSplit(pOrWc, pExpr, TK_OR);
sqlite3WhereExprAnalyze(pSrc, pOrWc);
if( db->mallocFailed ) return;
assert( pOrWc->nTerm>=2 );
/*
** Compute the set of tables that might satisfy cases 1 or 3.
*/
indexable = ~(Bitmask)0;
chngToIN = ~(Bitmask)0;
for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
WhereAndInfo *pAndInfo;
assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
chngToIN = 0;
pAndInfo = sqlite3DbMallocRaw(db, sizeof(*pAndInfo));
if( pAndInfo ){
WhereClause *pAndWC;
WhereTerm *pAndTerm;
int j;
Bitmask b = 0;
pOrTerm->u.pAndInfo = pAndInfo;
pOrTerm->wtFlags |= TERM_ANDINFO;
pOrTerm->eOperator = WO_AND;
pAndWC = &pAndInfo->wc;
sqlite3WhereClauseInit(pAndWC, pWC->pWInfo);
sqlite3WhereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
sqlite3WhereExprAnalyze(pSrc, pAndWC);
pAndWC->pOuter = pWC;
testcase( db->mallocFailed );
if( !db->mallocFailed ){
for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
assert( pAndTerm->pExpr );
if( allowedOp(pAndTerm->pExpr->op) ){
b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
}
}
}
indexable &= b;
}
}else if( pOrTerm->wtFlags & TERM_COPIED ){
/* Skip this term for now. We revisit it when we process the
** corresponding TERM_VIRTUAL term */
}else{
Bitmask b;
b = sqlite3WhereGetMask(&pWInfo->sMaskSet, pOrTerm->leftCursor);
if( pOrTerm->wtFlags & TERM_VIRTUAL ){
WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pOther->leftCursor);
}
indexable &= b;
if( (pOrTerm->eOperator & WO_EQ)==0 ){
chngToIN = 0;
}else{
chngToIN &= b;
}
}
}
/*
** Record the set of tables that satisfy case 3. The set might be
** empty.
*/
pOrInfo->indexable = indexable;
pTerm->eOperator = indexable==0 ? 0 : WO_OR;
/* For a two-way OR, attempt to implementation case 2.
*/
if( indexable && pOrWc->nTerm==2 ){
int iOne = 0;
WhereTerm *pOne;
while( (pOne = whereNthSubterm(&pOrWc->a[0],iOne++))!=0 ){
int iTwo = 0;
WhereTerm *pTwo;
while( (pTwo = whereNthSubterm(&pOrWc->a[1],iTwo++))!=0 ){
whereCombineDisjuncts(pSrc, pWC, pOne, pTwo);
}
}
}
/*
** chngToIN holds a set of tables that *might* satisfy case 1. But
** we have to do some additional checking to see if case 1 really
** is satisfied.
**
** chngToIN will hold either 0, 1, or 2 bits. The 0-bit case means
** that there is no possibility of transforming the OR clause into an
** IN operator because one or more terms in the OR clause contain
** something other than == on a column in the single table. The 1-bit
** case means that every term of the OR clause is of the form
** "table.column=expr" for some single table. The one bit that is set
** will correspond to the common table. We still need to check to make
** sure the same column is used on all terms. The 2-bit case is when
** the all terms are of the form "table1.column=table2.column". It
** might be possible to form an IN operator with either table1.column
** or table2.column as the LHS if either is common to every term of
** the OR clause.
**
** Note that terms of the form "table.column1=table.column2" (the
** same table on both sizes of the ==) cannot be optimized.
*/
if( chngToIN ){
int okToChngToIN = 0; /* True if the conversion to IN is valid */
int iColumn = -1; /* Column index on lhs of IN operator */
int iCursor = -1; /* Table cursor common to all terms */
int j = 0; /* Loop counter */
/* Search for a table and column that appears on one side or the
** other of the == operator in every subterm. That table and column
** will be recorded in iCursor and iColumn. There might not be any
** such table and column. Set okToChngToIN if an appropriate table
** and column is found but leave okToChngToIN false if not found.
*/
for(j=0; j<2 && !okToChngToIN; j++){
pOrTerm = pOrWc->a;
for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
assert( pOrTerm->eOperator & WO_EQ );
pOrTerm->wtFlags &= ~TERM_OR_OK;
if( pOrTerm->leftCursor==iCursor ){
/* This is the 2-bit case and we are on the second iteration and
** current term is from the first iteration. So skip this term. */
assert( j==1 );
continue;
}
if( (chngToIN & sqlite3WhereGetMask(&pWInfo->sMaskSet,
pOrTerm->leftCursor))==0 ){
/* This term must be of the form t1.a==t2.b where t2 is in the
** chngToIN set but t1 is not. This term will be either preceded
** or follwed by an inverted copy (t2.b==t1.a). Skip this term
** and use its inversion. */
testcase( pOrTerm->wtFlags & TERM_COPIED );
testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
continue;
}
iColumn = pOrTerm->u.leftColumn;
iCursor = pOrTerm->leftCursor;
break;
}
if( i<0 ){
/* No candidate table+column was found. This can only occur
** on the second iteration */
assert( j==1 );
assert( IsPowerOfTwo(chngToIN) );
assert( chngToIN==sqlite3WhereGetMask(&pWInfo->sMaskSet, iCursor) );
break;
}
testcase( j==1 );
/* We have found a candidate table and column. Check to see if that
** table and column is common to every term in the OR clause */
okToChngToIN = 1;
for(; i>=0 && okToChngToIN; i--, pOrTerm++){
assert( pOrTerm->eOperator & WO_EQ );
if( pOrTerm->leftCursor!=iCursor ){
pOrTerm->wtFlags &= ~TERM_OR_OK;
}else if( pOrTerm->u.leftColumn!=iColumn ){
okToChngToIN = 0;
}else{
int affLeft, affRight;
/* If the right-hand side is also a column, then the affinities
** of both right and left sides must be such that no type
** conversions are required on the right. (Ticket #2249)
*/
affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight);
affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft);
if( affRight!=0 && affRight!=affLeft ){
okToChngToIN = 0;
}else{
pOrTerm->wtFlags |= TERM_OR_OK;
}
}
}
}
/* At this point, okToChngToIN is true if original pTerm satisfies
** case 1. In that case, construct a new virtual term that is
** pTerm converted into an IN operator.
*/
if( okToChngToIN ){
Expr *pDup; /* A transient duplicate expression */
ExprList *pList = 0; /* The RHS of the IN operator */
Expr *pLeft = 0; /* The LHS of the IN operator */
Expr *pNew; /* The complete IN operator */
for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
assert( pOrTerm->eOperator & WO_EQ );
assert( pOrTerm->leftCursor==iCursor );
assert( pOrTerm->u.leftColumn==iColumn );
pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0);
pList = sqlite3ExprListAppend(pWInfo->pParse, pList, pDup);
pLeft = pOrTerm->pExpr->pLeft;
}
assert( pLeft!=0 );
pDup = sqlite3ExprDup(db, pLeft, 0);
pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0, 0);
if( pNew ){
int idxNew;
transferJoinMarkings(pNew, pExpr);
assert( !ExprHasProperty(pNew, EP_xIsSelect) );
pNew->x.pList = pList;
idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
testcase( idxNew==0 );
exprAnalyze(pSrc, pWC, idxNew);
pTerm = &pWC->a[idxTerm];
markTermAsChild(pWC, idxNew, idxTerm);
}else{
sqlite3ExprListDelete(db, pList);
}
pTerm->eOperator = WO_NOOP; /* case 1 trumps case 3 */
}
}
}
/*
** Create a new sqlite3_value object, containing the value of pExpr.
**
** This only works for very simple expressions that consist of one constant
** token (i.e. "5", "5.1", "'a string'"). If the expression can
** be converted directly into a value, then the value is allocated and
** a pointer written to *ppVal. The caller is responsible for deallocating
** the value by passing it to sqlite3ValueFree() later on. If the expression
** cannot be converted to a value, then *ppVal is set to NULL.
*/
int sqlite3ValueFromExpr(
sqlite3 *db, /* The database connection */
Expr *pExpr, /* The expression to evaluate */
u8 enc, /* Encoding to use */
u8 affinity, /* Affinity to use */
sqlite3_value **ppVal /* Write the new value here */
){
int op;
char *zVal = 0;
sqlite3_value *pVal = 0;
if( !pExpr ){
*ppVal = 0;
return SQLITE_OK;
}
op = pExpr->op;
if( op==TK_REGISTER ){
op = pExpr->op2;
}
if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
pVal = sqlite3ValueNew(db);
if( pVal==0 ) goto no_mem;
if( ExprHasProperty(pExpr, EP_IntValue) ){
sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue);
}else{
zVal = sqlite3DbStrDup(db, pExpr->u.zToken);
if( zVal==0 ) goto no_mem;
sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
if( op==TK_FLOAT ) pVal->type = SQLITE_FLOAT;
}
if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
}else{
sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
}
if( enc!=SQLITE_UTF8 ){
sqlite3VdbeChangeEncoding(pVal, enc);
}
}else if( op==TK_UMINUS ) {
if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
pVal->u.i = -1 * pVal->u.i;
/* (double)-1 In case of SQLITE_OMIT_FLOATING_POINT... */
pVal->r = (double)-1 * pVal->r;
}
}
#ifndef SQLITE_OMIT_BLOB_LITERAL
else if( op==TK_BLOB ){
int nVal;
assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
assert( pExpr->u.zToken[1]=='\'' );
pVal = sqlite3ValueNew(db);
if( !pVal ) goto no_mem;
zVal = &pExpr->u.zToken[2];
nVal = sqlite3Strlen30(zVal)-1;
assert( zVal[nVal]=='\'' );
sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
0, SQLITE_DYNAMIC);
}
#endif
*ppVal = pVal;
return SQLITE_OK;
no_mem:
db->mallocFailed = 1;
sqlite3DbFree(db, zVal);
sqlite3ValueFree(pVal);
*ppVal = 0;
return SQLITE_NOMEM;
}
/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an (opaque) structure that contains
** information needed to terminate the loop. Later, the calling routine
** should invoke sqliteWhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
**
** If an error occurs, this routine returns NULL.
**
** The basic idea is to do a nested loop, one loop for each table in
** the FROM clause of a select. (INSERT and UPDATE statements are the
** same as a SELECT with only a single table in the FROM clause.) For
** example, if the SQL is this:
**
** SELECT * FROM t1, t2, t3 WHERE ...;
**
** Then the code generated is conceptually like the following:
**
** foreach row1 in t1 do \ Code generated
** foreach row2 in t2 do |-- by sqliteWhereBegin()
** foreach row3 in t3 do /
** ...
** end \ Code generated
** end |-- by sqliteWhereEnd()
** end /
**
** There are Btree cursors associated with each table. t1 uses cursor
** number pTabList->a[0].iCursor. t2 uses the cursor pTabList->a[1].iCursor.
** And so forth. This routine generates code to open those VDBE cursors
** and sqliteWhereEnd() generates the code to close them.
**
** If the WHERE clause is empty, the foreach loops must each scan their
** entire tables. Thus a three-way join is an O(N^3) operation. But if
** the tables have indices and there are terms in the WHERE clause that
** refer to those indices, a complete table scan can be avoided and the
** code will run much faster. Most of the work of this routine is checking
** to see if there are indices that can be used to speed up the loop.
**
** Terms of the WHERE clause are also used to limit which rows actually
** make it to the "..." in the middle of the loop. After each "foreach",
** terms of the WHERE clause that use only terms in that loop and outer
** loops are evaluated and if false a jump is made around all subsequent
** inner loops (or around the "..." if the test occurs within the inner-
** most loop)
**
** OUTER JOINS
**
** An outer join of tables t1 and t2 is conceptally coded as follows:
**
** foreach row1 in t1 do
** flag = 0
** foreach row2 in t2 do
** start:
** ...
** flag = 1
** end
** if flag==0 then
** move the row2 cursor to a null row
** goto start
** fi
** end
**
** ORDER BY CLAUSE PROCESSING
**
** *ppOrderBy is a pointer to the ORDER BY clause of a SELECT statement,
** if there is one. If there is no ORDER BY clause or if this routine
** is called from an UPDATE or DELETE statement, then ppOrderBy is NULL.
**
** If an index can be used so that the natural output order of the table
** scan is correct for the ORDER BY clause, then that index is used and
** *ppOrderBy is set to NULL. This is an optimization that prevents an
** unnecessary sort of the result set if an index appropriate for the
** ORDER BY clause already exists.
**
** If the where clause loops cannot be arranged to provide the correct
** output order, then the *ppOrderBy is unchanged.
*/
WhereInfo *sqliteWhereBegin(
Parse *pParse, /* The parser context */
SrcList *pTabList, /* A list of all tables to be scanned */
Expr *pWhere, /* The WHERE clause */
int pushKey, /* If TRUE, leave the table key on the stack */
ExprList **ppOrderBy /* An ORDER BY clause, or NULL */
){
int i; /* Loop counter */
WhereInfo *pWInfo; /* Will become the return value of this function */
Vdbe *v = pParse->pVdbe; /* The virtual database engine */
int brk, cont = 0; /* Addresses used during code generation */
int nExpr; /* Number of subexpressions in the WHERE clause */
int loopMask; /* One bit set for each outer loop */
int haveKey; /* True if KEY is on the stack */
ExprMaskSet maskSet; /* The expression mask set */
int iDirectEq[32]; /* Term of the form ROWID==X for the N-th table */
int iDirectLt[32]; /* Term of the form ROWID<X or ROWID<=X */
int iDirectGt[32]; /* Term of the form ROWID>X or ROWID>=X */
ExprInfo aExpr[101]; /* The WHERE clause is divided into these expressions */
/* pushKey is only allowed if there is a single table (as in an INSERT or
** UPDATE statement)
*/
assert( pushKey==0 || pTabList->nSrc==1 );
/* Split the WHERE clause into separate subexpressions where each
** subexpression is separated by an AND operator. If the aExpr[]
** array fills up, the last entry might point to an expression which
** contains additional unfactored AND operators.
*/
initMaskSet(&maskSet);
memset(aExpr, 0, sizeof(aExpr));
nExpr = exprSplit(ARRAYSIZE(aExpr), aExpr, pWhere);
if( nExpr==ARRAYSIZE(aExpr) ){
sqliteErrorMsg(pParse, "WHERE clause too complex - no more "
"than %d terms allowed", (int)ARRAYSIZE(aExpr)-1);
return 0;
}
/* Allocate and initialize the WhereInfo structure that will become the
** return value.
*/
pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
if( sqlite_malloc_failed ){
sqliteFree(pWInfo);
return 0;
}
pWInfo->pParse = pParse;
pWInfo->pTabList = pTabList;
pWInfo->peakNTab = pWInfo->savedNTab = pParse->nTab;
pWInfo->iBreak = sqliteVdbeMakeLabel(v);
/* Special case: a WHERE clause that is constant. Evaluate the
** expression and either jump over all of the code or fall thru.
*/
if( pWhere && (pTabList->nSrc==0 || sqliteExprIsConstant(pWhere)) ){
sqliteExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
pWhere = 0;
}
/* Analyze all of the subexpressions.
*/
for(i=0; i<nExpr; i++){
exprAnalyze(&maskSet, &aExpr[i]);
/* If we are executing a trigger body, remove all references to
** new.* and old.* tables from the prerequisite masks.
*/
if( pParse->trigStack ){
int x;
if( (x = pParse->trigStack->newIdx) >= 0 ){
int mask = ~getMask(&maskSet, x);
aExpr[i].prereqRight &= mask;
aExpr[i].prereqLeft &= mask;
aExpr[i].prereqAll &= mask;
}
if( (x = pParse->trigStack->oldIdx) >= 0 ){
int mask = ~getMask(&maskSet, x);
aExpr[i].prereqRight &= mask;
aExpr[i].prereqLeft &= mask;
aExpr[i].prereqAll &= mask;
}
}
}
/* Figure out what index to use (if any) for each nested loop.
** Make pWInfo->a[i].pIdx point to the index to use for the i-th nested
** loop where i==0 is the outer loop and i==pTabList->nSrc-1 is the inner
** loop.
**
** If terms exist that use the ROWID of any table, then set the
** iDirectEq[], iDirectLt[], or iDirectGt[] elements for that table
** to the index of the term containing the ROWID. We always prefer
** to use a ROWID which can directly access a table rather than an
** index which requires reading an index first to get the rowid then
** doing a second read of the actual database table.
**
** Actually, if there are more than 32 tables in the join, only the
** first 32 tables are candidates for indices. This is (again) due
** to the limit of 32 bits in an integer bitmask.
*/
loopMask = 0;
for(i=0; i<pTabList->nSrc && i<ARRAYSIZE(iDirectEq); i++){
int j;
int iCur = pTabList->a[i].iCursor; /* The cursor for this table */
int mask = getMask(&maskSet, iCur); /* Cursor mask for this table */
Table *pTab = pTabList->a[i].pTab;
Index *pIdx;
Index *pBestIdx = 0;
int bestScore = 0;
/* Check to see if there is an expression that uses only the
** ROWID field of this table. For terms of the form ROWID==expr
** set iDirectEq[i] to the index of the term. For terms of the
** form ROWID<expr or ROWID<=expr set iDirectLt[i] to the term index.
** For terms like ROWID>expr or ROWID>=expr set iDirectGt[i].
**
** (Added:) Treat ROWID IN expr like ROWID=expr.
*/
pWInfo->a[i].iCur = -1;
iDirectEq[i] = -1;
iDirectLt[i] = -1;
iDirectGt[i] = -1;
for(j=0; j<nExpr; j++){
if( aExpr[j].idxLeft==iCur && aExpr[j].p->pLeft->iColumn<0
&& (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
switch( aExpr[j].p->op ){
case TK_IN:
case TK_EQ: iDirectEq[i] = j; break;
case TK_LE:
case TK_LT: iDirectLt[i] = j; break;
case TK_GE:
case TK_GT: iDirectGt[i] = j; break;
}
}
if( aExpr[j].idxRight==iCur && aExpr[j].p->pRight->iColumn<0
&& (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
switch( aExpr[j].p->op ){
case TK_EQ: iDirectEq[i] = j; break;
case TK_LE:
case TK_LT: iDirectGt[i] = j; break;
case TK_GE:
case TK_GT: iDirectLt[i] = j; break;
}
}
}
if( iDirectEq[i]>=0 ){
loopMask |= mask;
pWInfo->a[i].pIdx = 0;
continue;
}
/* Do a search for usable indices. Leave pBestIdx pointing to
** the "best" index. pBestIdx is left set to NULL if no indices
** are usable.
**
** The best index is determined as follows. For each of the
** left-most terms that is fixed by an equality operator, add
** 8 to the score. The right-most term of the index may be
** constrained by an inequality. Add 1 if for an "x<..." constraint
** and add 2 for an "x>..." constraint. Chose the index that
** gives the best score.
**
** This scoring system is designed so that the score can later be
** used to determine how the index is used. If the score&7 is 0
** then all constraints are equalities. If score&1 is not 0 then
** there is an inequality used as a termination key. (ex: "x<...")
** If score&2 is not 0 then there is an inequality used as the
** start key. (ex: "x>..."). A score or 4 is the special case
** of an IN operator constraint. (ex: "x IN ...").
**
** The IN operator (as in "<expr> IN (...)") is treated the same as
** an equality comparison except that it can only be used on the
** left-most column of an index and other terms of the WHERE clause
** cannot be used in conjunction with the IN operator to help satisfy
** other columns of the index.
*/
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
int eqMask = 0; /* Index columns covered by an x=... term */
int ltMask = 0; /* Index columns covered by an x<... term */
int gtMask = 0; /* Index columns covered by an x>... term */
int inMask = 0; /* Index columns covered by an x IN .. term */
int nEq, m, score;
if( pIdx->nColumn>32 ) continue; /* Ignore indices too many columns */
for(j=0; j<nExpr; j++){
if( aExpr[j].idxLeft==iCur
&& (aExpr[j].prereqRight & loopMask)==aExpr[j].prereqRight ){
int iColumn = aExpr[j].p->pLeft->iColumn;
int k;
for(k=0; k<pIdx->nColumn; k++){
if( pIdx->aiColumn[k]==iColumn ){
switch( aExpr[j].p->op ){
case TK_IN: {
if( k==0 ) inMask |= 1;
break;
}
case TK_EQ: {
eqMask |= 1<<k;
break;
}
case TK_LE:
case TK_LT: {
ltMask |= 1<<k;
break;
}
case TK_GE:
case TK_GT: {
gtMask |= 1<<k;
break;
}
default: {
/* CANT_HAPPEN */
assert( 0 );
break;
}
}
break;
}
}
}
if( aExpr[j].idxRight==iCur
&& (aExpr[j].prereqLeft & loopMask)==aExpr[j].prereqLeft ){
int iColumn = aExpr[j].p->pRight->iColumn;
int k;
for(k=0; k<pIdx->nColumn; k++){
if( pIdx->aiColumn[k]==iColumn ){
switch( aExpr[j].p->op ){
case TK_EQ: {
eqMask |= 1<<k;
break;
}
case TK_LE:
case TK_LT: {
gtMask |= 1<<k;
break;
}
case TK_GE:
case TK_GT: {
ltMask |= 1<<k;
break;
}
default: {
/* CANT_HAPPEN */
assert( 0 );
break;
}
}
break;
}
}
}
}
/* The following loop ends with nEq set to the number of columns
** on the left of the index with == constraints.
*/
for(nEq=0; nEq<pIdx->nColumn; nEq++){
m = (1<<(nEq+1))-1;
if( (m & eqMask)!=m ) break;
}
score = nEq*8; /* Base score is 8 times number of == constraints */
m = 1<<nEq;
if( m & ltMask ) score++; /* Increase score for a < constraint */
if( m & gtMask ) score+=2; /* Increase score for a > constraint */
if( score==0 && inMask ) score = 4; /* Default score for IN constraint */
if( score>bestScore ){
pBestIdx = pIdx;
bestScore = score;
}
}
pWInfo->a[i].pIdx = pBestIdx;
pWInfo->a[i].score = bestScore;
pWInfo->a[i].bRev = 0;
loopMask |= mask;
if( pBestIdx ){
pWInfo->a[i].iCur = pParse->nTab++;
pWInfo->peakNTab = pParse->nTab;
}
}
/* Check to see if the ORDER BY clause is or can be satisfied by the
** use of an index on the first table.
*/
if( ppOrderBy && *ppOrderBy && pTabList->nSrc>0 ){
Index *pSortIdx;
Index *pIdx;
Table *pTab;
int bRev = 0;
pTab = pTabList->a[0].pTab;
pIdx = pWInfo->a[0].pIdx;
if( pIdx && pWInfo->a[0].score==4 ){
/* If there is already an IN index on the left-most table,
** it will not give the correct sort order.
** So, pretend that no suitable index is found.
*/
pSortIdx = 0;
}else if( iDirectEq[0]>=0 || iDirectLt[0]>=0 || iDirectGt[0]>=0 ){
/* If the left-most column is accessed using its ROWID, then do
** not try to sort by index.
*/
pSortIdx = 0;
}else{
int nEqCol = (pWInfo->a[0].score+4)/8;
pSortIdx = findSortingIndex(pTab, pTabList->a[0].iCursor,
*ppOrderBy, pIdx, nEqCol, &bRev);
}
if( pSortIdx && (pIdx==0 || pIdx==pSortIdx) ){
if( pIdx==0 ){
pWInfo->a[0].pIdx = pSortIdx;
pWInfo->a[0].iCur = pParse->nTab++;
pWInfo->peakNTab = pParse->nTab;
}
pWInfo->a[0].bRev = bRev;
*ppOrderBy = 0;
}
}
/* Open all tables in the pTabList and all indices used by those tables.
*/
for(i=0; i<pTabList->nSrc; i++){
Table *pTab;
Index *pIx;
pTab = pTabList->a[i].pTab;
if( pTab->isTransient || pTab->pSelect ) continue;
sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0);
sqliteVdbeOp3(v, OP_OpenRead, pTabList->a[i].iCursor, pTab->tnum,
pTab->zName, P3_STATIC);
sqliteCodeVerifySchema(pParse, pTab->iDb);
if( (pIx = pWInfo->a[i].pIdx)!=0 ){
sqliteVdbeAddOp(v, OP_Integer, pIx->iDb, 0);
sqliteVdbeOp3(v, OP_OpenRead, pWInfo->a[i].iCur, pIx->tnum, pIx->zName,0);
}
}
/* Generate the code to do the search
*/
loopMask = 0;
for(i=0; i<pTabList->nSrc; i++){
int j, k;
int iCur = pTabList->a[i].iCursor;
Index *pIdx;
WhereLevel *pLevel = &pWInfo->a[i];
/* If this is the right table of a LEFT OUTER JOIN, allocate and
** initialize a memory cell that records if this table matches any
** row of the left table of the join.
*/
if( i>0 && (pTabList->a[i-1].jointype & JT_LEFT)!=0 ){
if( !pParse->nMem ) pParse->nMem++;
pLevel->iLeftJoin = pParse->nMem++;
sqliteVdbeAddOp(v, OP_String, 0, 0);
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
}
pIdx = pLevel->pIdx;
pLevel->inOp = OP_Noop;
if( i<ARRAYSIZE(iDirectEq) && iDirectEq[i]>=0 ){
/* Case 1: We can directly reference a single row using an
** equality comparison against the ROWID field. Or
** we reference multiple rows using a "rowid IN (...)"
** construct.
*/
k = iDirectEq[i];
assert( k<nExpr );
assert( aExpr[k].p!=0 );
assert( aExpr[k].idxLeft==iCur || aExpr[k].idxRight==iCur );
brk = pLevel->brk = sqliteVdbeMakeLabel(v);
if( aExpr[k].idxLeft==iCur ){
Expr *pX = aExpr[k].p;
if( pX->op!=TK_IN ){
sqliteExprCode(pParse, aExpr[k].p->pRight);
}else if( pX->pList ){
sqliteVdbeAddOp(v, OP_SetFirst, pX->iTable, brk);
pLevel->inOp = OP_SetNext;
pLevel->inP1 = pX->iTable;
pLevel->inP2 = sqliteVdbeCurrentAddr(v);
}else{
assert( pX->pSelect );
sqliteVdbeAddOp(v, OP_Rewind, pX->iTable, brk);
sqliteVdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
pLevel->inP2 = sqliteVdbeAddOp(v, OP_FullKey, pX->iTable, 0);
pLevel->inOp = OP_Next;
pLevel->inP1 = pX->iTable;
}
}else{
sqliteExprCode(pParse, aExpr[k].p->pLeft);
}
disableTerm(pLevel, &aExpr[k].p);
cont = pLevel->cont = sqliteVdbeMakeLabel(v);
sqliteVdbeAddOp(v, OP_MustBeInt, 1, brk);
haveKey = 0;
sqliteVdbeAddOp(v, OP_NotExists, iCur, brk);
pLevel->op = OP_Noop;
}else if( pIdx!=0 && pLevel->score>0 && pLevel->score%4==0 ){
/* Case 2: There is an index and all terms of the WHERE clause that
** refer to the index use the "==" or "IN" operators.
*/
int start;
int testOp;
int nColumn = (pLevel->score+4)/8;
brk = pLevel->brk = sqliteVdbeMakeLabel(v);
for(j=0; j<nColumn; j++){
for(k=0; k<nExpr; k++){
Expr *pX = aExpr[k].p;
if( pX==0 ) continue;
if( aExpr[k].idxLeft==iCur
&& (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight
&& pX->pLeft->iColumn==pIdx->aiColumn[j]
){
if( pX->op==TK_EQ ){
sqliteExprCode(pParse, pX->pRight);
disableTerm(pLevel, &aExpr[k].p);
break;
}
if( pX->op==TK_IN && nColumn==1 ){
if( pX->pList ){
sqliteVdbeAddOp(v, OP_SetFirst, pX->iTable, brk);
pLevel->inOp = OP_SetNext;
pLevel->inP1 = pX->iTable;
pLevel->inP2 = sqliteVdbeCurrentAddr(v);
}else{
assert( pX->pSelect );
sqliteVdbeAddOp(v, OP_Rewind, pX->iTable, brk);
sqliteVdbeAddOp(v, OP_KeyAsData, pX->iTable, 1);
pLevel->inP2 = sqliteVdbeAddOp(v, OP_FullKey, pX->iTable, 0);
pLevel->inOp = OP_Next;
pLevel->inP1 = pX->iTable;
}
disableTerm(pLevel, &aExpr[k].p);
break;
}
}
if( aExpr[k].idxRight==iCur
&& aExpr[k].p->op==TK_EQ
&& (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
&& aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, aExpr[k].p->pLeft);
disableTerm(pLevel, &aExpr[k].p);
break;
}
}
}
pLevel->iMem = pParse->nMem++;
cont = pLevel->cont = sqliteVdbeMakeLabel(v);
sqliteVdbeAddOp(v, OP_NotNull, -nColumn, sqliteVdbeCurrentAddr(v)+3);
sqliteVdbeAddOp(v, OP_Pop, nColumn, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, brk);
sqliteVdbeAddOp(v, OP_MakeKey, nColumn, 0);
sqliteAddIdxKeyType(v, pIdx);
if( nColumn==pIdx->nColumn || pLevel->bRev ){
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);
testOp = OP_IdxGT;
}else{
sqliteVdbeAddOp(v, OP_Dup, 0, 0);
sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
testOp = OP_IdxGE;
}
if( pLevel->bRev ){
/* Scan in reverse order */
sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
sqliteVdbeAddOp(v, OP_MoveLt, pLevel->iCur, brk);
start = sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
sqliteVdbeAddOp(v, OP_IdxLT, pLevel->iCur, brk);
pLevel->op = OP_Prev;
}else{
/* Scan in the forward order */
sqliteVdbeAddOp(v, OP_MoveTo, pLevel->iCur, brk);
start = sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
sqliteVdbeAddOp(v, testOp, pLevel->iCur, brk);
pLevel->op = OP_Next;
}
sqliteVdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
sqliteVdbeAddOp(v, OP_IdxIsNull, nColumn, cont);
sqliteVdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
if( i==pTabList->nSrc-1 && pushKey ){
haveKey = 1;
}else{
sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0);
haveKey = 0;
}
pLevel->p1 = pLevel->iCur;
pLevel->p2 = start;
}else if( i<ARRAYSIZE(iDirectLt) && (iDirectLt[i]>=0 || iDirectGt[i]>=0) ){
/* Case 3: We have an inequality comparison against the ROWID field.
*/
int testOp = OP_Noop;
int start;
brk = pLevel->brk = sqliteVdbeMakeLabel(v);
cont = pLevel->cont = sqliteVdbeMakeLabel(v);
if( iDirectGt[i]>=0 ){
k = iDirectGt[i];
assert( k<nExpr );
assert( aExpr[k].p!=0 );
assert( aExpr[k].idxLeft==iCur || aExpr[k].idxRight==iCur );
if( aExpr[k].idxLeft==iCur ){
sqliteExprCode(pParse, aExpr[k].p->pRight);
}else{
sqliteExprCode(pParse, aExpr[k].p->pLeft);
}
sqliteVdbeAddOp(v, OP_ForceInt,
aExpr[k].p->op==TK_LT || aExpr[k].p->op==TK_GT, brk);
sqliteVdbeAddOp(v, OP_MoveTo, iCur, brk);
disableTerm(pLevel, &aExpr[k].p);
}else{
sqliteVdbeAddOp(v, OP_Rewind, iCur, brk);
}
if( iDirectLt[i]>=0 ){
k = iDirectLt[i];
assert( k<nExpr );
assert( aExpr[k].p!=0 );
assert( aExpr[k].idxLeft==iCur || aExpr[k].idxRight==iCur );
if( aExpr[k].idxLeft==iCur ){
sqliteExprCode(pParse, aExpr[k].p->pRight);
}else{
sqliteExprCode(pParse, aExpr[k].p->pLeft);
}
/* sqliteVdbeAddOp(v, OP_MustBeInt, 0, sqliteVdbeCurrentAddr(v)+1); */
pLevel->iMem = pParse->nMem++;
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
if( aExpr[k].p->op==TK_LT || aExpr[k].p->op==TK_GT ){
testOp = OP_Ge;
}else{
testOp = OP_Gt;
}
disableTerm(pLevel, &aExpr[k].p);
}
start = sqliteVdbeCurrentAddr(v);
pLevel->op = OP_Next;
pLevel->p1 = iCur;
pLevel->p2 = start;
if( testOp!=OP_Noop ){
sqliteVdbeAddOp(v, OP_Recno, iCur, 0);
sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
sqliteVdbeAddOp(v, testOp, 0, brk);
}
haveKey = 0;
}else if( pIdx==0 ){
/* Case 4: There is no usable index. We must do a complete
** scan of the entire database table.
*/
int start;
brk = pLevel->brk = sqliteVdbeMakeLabel(v);
cont = pLevel->cont = sqliteVdbeMakeLabel(v);
sqliteVdbeAddOp(v, OP_Rewind, iCur, brk);
start = sqliteVdbeCurrentAddr(v);
pLevel->op = OP_Next;
pLevel->p1 = iCur;
pLevel->p2 = start;
haveKey = 0;
}else{
/* Case 5: The WHERE clause term that refers to the right-most
** column of the index is an inequality. For example, if
** the index is on (x,y,z) and the WHERE clause is of the
** form "x=5 AND y<10" then this case is used. Only the
** right-most column can be an inequality - the rest must
** use the "==" operator.
**
** This case is also used when there are no WHERE clause
** constraints but an index is selected anyway, in order
** to force the output order to conform to an ORDER BY.
*/
int score = pLevel->score;
int nEqColumn = score/8;
int start;
int leFlag, geFlag;
int testOp;
/* Evaluate the equality constraints
*/
for(j=0; j<nEqColumn; j++){
for(k=0; k<nExpr; k++){
if( aExpr[k].p==0 ) continue;
if( aExpr[k].idxLeft==iCur
&& aExpr[k].p->op==TK_EQ
&& (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight
&& aExpr[k].p->pLeft->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, aExpr[k].p->pRight);
disableTerm(pLevel, &aExpr[k].p);
break;
}
if( aExpr[k].idxRight==iCur
&& aExpr[k].p->op==TK_EQ
&& (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
&& aExpr[k].p->pRight->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, aExpr[k].p->pLeft);
disableTerm(pLevel, &aExpr[k].p);
break;
}
}
}
/* Duplicate the equality term values because they will all be
** used twice: once to make the termination key and once to make the
** start key.
*/
for(j=0; j<nEqColumn; j++){
sqliteVdbeAddOp(v, OP_Dup, nEqColumn-1, 0);
}
/* Labels for the beginning and end of the loop
*/
cont = pLevel->cont = sqliteVdbeMakeLabel(v);
brk = pLevel->brk = sqliteVdbeMakeLabel(v);
/* Generate the termination key. This is the key value that
** will end the search. There is no termination key if there
** are no equality terms and no "X<..." term.
**
** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
** key computed here really ends up being the start key.
*/
if( (score & 1)!=0 ){
for(k=0; k<nExpr; k++){
Expr *pExpr = aExpr[k].p;
if( pExpr==0 ) continue;
if( aExpr[k].idxLeft==iCur
&& (pExpr->op==TK_LT || pExpr->op==TK_LE)
&& (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight
&& pExpr->pLeft->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, pExpr->pRight);
leFlag = pExpr->op==TK_LE;
disableTerm(pLevel, &aExpr[k].p);
break;
}
if( aExpr[k].idxRight==iCur
&& (pExpr->op==TK_GT || pExpr->op==TK_GE)
&& (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
&& pExpr->pRight->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, pExpr->pLeft);
leFlag = pExpr->op==TK_GE;
disableTerm(pLevel, &aExpr[k].p);
break;
}
}
testOp = OP_IdxGE;
}else{
testOp = nEqColumn>0 ? OP_IdxGE : OP_Noop;
leFlag = 1;
}
if( testOp!=OP_Noop ){
int nCol = nEqColumn + (score & 1);
pLevel->iMem = pParse->nMem++;
sqliteVdbeAddOp(v, OP_NotNull, -nCol, sqliteVdbeCurrentAddr(v)+3);
sqliteVdbeAddOp(v, OP_Pop, nCol, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, brk);
sqliteVdbeAddOp(v, OP_MakeKey, nCol, 0);
sqliteAddIdxKeyType(v, pIdx);
if( leFlag ){
sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
}
if( pLevel->bRev ){
sqliteVdbeAddOp(v, OP_MoveLt, pLevel->iCur, brk);
}else{
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
}
}else if( pLevel->bRev ){
sqliteVdbeAddOp(v, OP_Last, pLevel->iCur, brk);
}
/* Generate the start key. This is the key that defines the lower
** bound on the search. There is no start key if there are no
** equality terms and if there is no "X>..." term. In
** that case, generate a "Rewind" instruction in place of the
** start key search.
**
** 2002-Dec-04: In the case of a reverse-order search, the so-called
** "start" key really ends up being used as the termination key.
*/
if( (score & 2)!=0 ){
for(k=0; k<nExpr; k++){
Expr *pExpr = aExpr[k].p;
if( pExpr==0 ) continue;
if( aExpr[k].idxLeft==iCur
&& (pExpr->op==TK_GT || pExpr->op==TK_GE)
&& (aExpr[k].prereqRight & loopMask)==aExpr[k].prereqRight
&& pExpr->pLeft->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, pExpr->pRight);
geFlag = pExpr->op==TK_GE;
disableTerm(pLevel, &aExpr[k].p);
break;
}
if( aExpr[k].idxRight==iCur
&& (pExpr->op==TK_LT || pExpr->op==TK_LE)
&& (aExpr[k].prereqLeft & loopMask)==aExpr[k].prereqLeft
&& pExpr->pRight->iColumn==pIdx->aiColumn[j]
){
sqliteExprCode(pParse, pExpr->pLeft);
geFlag = pExpr->op==TK_LE;
disableTerm(pLevel, &aExpr[k].p);
break;
}
}
}else{
geFlag = 1;
}
if( nEqColumn>0 || (score&2)!=0 ){
int nCol = nEqColumn + ((score&2)!=0);
sqliteVdbeAddOp(v, OP_NotNull, -nCol, sqliteVdbeCurrentAddr(v)+3);
sqliteVdbeAddOp(v, OP_Pop, nCol, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, brk);
sqliteVdbeAddOp(v, OP_MakeKey, nCol, 0);
sqliteAddIdxKeyType(v, pIdx);
if( !geFlag ){
sqliteVdbeAddOp(v, OP_IncrKey, 0, 0);
}
if( pLevel->bRev ){
pLevel->iMem = pParse->nMem++;
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
testOp = OP_IdxLT;
}else{
sqliteVdbeAddOp(v, OP_MoveTo, pLevel->iCur, brk);
}
}else if( pLevel->bRev ){
testOp = OP_Noop;
}else{
sqliteVdbeAddOp(v, OP_Rewind, pLevel->iCur, brk);
}
/* Generate the the top of the loop. If there is a termination
** key we have to test for that key and abort at the top of the
** loop.
*/
start = sqliteVdbeCurrentAddr(v);
if( testOp!=OP_Noop ){
sqliteVdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
sqliteVdbeAddOp(v, testOp, pLevel->iCur, brk);
}
sqliteVdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
sqliteVdbeAddOp(v, OP_IdxIsNull, nEqColumn + (score & 1), cont);
sqliteVdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
if( i==pTabList->nSrc-1 && pushKey ){
haveKey = 1;
}else{
sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0);
haveKey = 0;
}
/* Record the instruction used to terminate the loop.
*/
pLevel->op = pLevel->bRev ? OP_Prev : OP_Next;
pLevel->p1 = pLevel->iCur;
pLevel->p2 = start;
}
loopMask |= getMask(&maskSet, iCur);
/* Insert code to test every subexpression that can be completely
** computed using the current set of tables.
*/
for(j=0; j<nExpr; j++){
if( aExpr[j].p==0 ) continue;
if( (aExpr[j].prereqAll & loopMask)!=aExpr[j].prereqAll ) continue;
if( pLevel->iLeftJoin && !ExprHasProperty(aExpr[j].p,EP_FromJoin) ){
continue;
}
if( haveKey ){
haveKey = 0;
sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0);
}
sqliteExprIfFalse(pParse, aExpr[j].p, cont, 1);
aExpr[j].p = 0;
}
brk = cont;
/* For a LEFT OUTER JOIN, generate code that will record the fact that
** at least one row of the right table has matched the left table.
*/
if( pLevel->iLeftJoin ){
pLevel->top = sqliteVdbeCurrentAddr(v);
sqliteVdbeAddOp(v, OP_Integer, 1, 0);
sqliteVdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
for(j=0; j<nExpr; j++){
if( aExpr[j].p==0 ) continue;
if( (aExpr[j].prereqAll & loopMask)!=aExpr[j].prereqAll ) continue;
if( haveKey ){
/* Cannot happen. "haveKey" can only be true if pushKey is true
** an pushKey can only be true for DELETE and UPDATE and there are
** no outer joins with DELETE and UPDATE.
*/
haveKey = 0;
sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0);
}
sqliteExprIfFalse(pParse, aExpr[j].p, cont, 1);
aExpr[j].p = 0;
}
}
}
pWInfo->iContinue = cont;
if( pushKey && !haveKey ){
sqliteVdbeAddOp(v, OP_Recno, pTabList->a[0].iCursor, 0);
}
freeMaskSet(&maskSet);
return pWInfo;
}
/*
** Disable a term in the WHERE clause. Except, do not disable the term
** if it controls a LEFT OUTER JOIN and it did not originate in the ON
** or USING clause of that join.
**
** Consider the term t2.z='ok' in the following queries:
**
** (1) SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x WHERE t2.z='ok'
** (2) SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x AND t2.z='ok'
** (3) SELECT * FROM t1, t2 WHERE t1.a=t2.x AND t2.z='ok'
**
** The t2.z='ok' is disabled in the in (2) because it did not originate
** in the ON clause. The term is disabled in (3) because it is not part
** of a LEFT OUTER JOIN. In (1), the term is not disabled.
**
** Disabling a term causes that term to not be tested in the inner loop
** of the join. Disabling is an optimization. We would get the correct
** results if nothing were ever disabled, but joins might run a little
** slower. The trick is to disable as much as we can without disabling
** too much. If we disabled in (1), we'd get the wrong answer.
** See ticket #813.
*/
static void disableTerm(WhereLevel *pLevel, Expr **ppExpr){
Expr *pExpr = *ppExpr;
if( pLevel->iLeftJoin==0 || ExprHasProperty(pExpr, EP_FromJoin) ){
*ppExpr = 0;
}
}
/*
** This routine is callback for sqlite3WalkExpr().
**
** Resolve symbolic names into TK_COLUMN operators for the current
** node in the expression tree. Return 0 to continue the search down
** the tree or 2 to abort the tree walk.
**
** This routine also does error checking and name resolution for
** function names. The operator for aggregate functions is changed
** to TK_AGG_FUNCTION.
*/
static int resolveExprStep(Walker *pWalker, Expr *pExpr){
NameContext *pNC;
Parse *pParse;
pNC = pWalker->u.pNC;
assert( pNC!=0 );
pParse = pNC->pParse;
assert( pParse==pWalker->pParse );
if( ExprHasProperty(pExpr, EP_Resolved) ) return WRC_Prune;
ExprSetProperty(pExpr, EP_Resolved);
#ifndef NDEBUG
if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){
SrcList *pSrcList = pNC->pSrcList;
int i;
for(i=0; i<pNC->pSrcList->nSrc; i++){
assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab);
}
}
#endif
switch( pExpr->op ){
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
/* The special operator TK_ROW means use the rowid for the first
** column in the FROM clause. This is used by the LIMIT and ORDER BY
** clause processing on UPDATE and DELETE statements.
*/
case TK_ROW: {
SrcList *pSrcList = pNC->pSrcList;
struct SrcList_item *pItem;
assert( pSrcList && pSrcList->nSrc==1 );
pItem = pSrcList->a;
pExpr->op = TK_COLUMN;
pExpr->pTab = pItem->pTab;
pExpr->iTable = pItem->iCursor;
pExpr->iColumn = -1;
pExpr->affinity = SQLITE_AFF_INTEGER;
break;
}
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) */
/* A lone identifier is the name of a column.
*/
case TK_ID: {
return lookupName(pParse, 0, 0, pExpr->u.zToken, pNC, pExpr);
}
/* A table name and column name: ID.ID
** Or a database, table and column: ID.ID.ID
*/
case TK_DOT: {
const char *zColumn;
const char *zTable;
const char *zDb;
Expr *pRight;
/* if( pSrcList==0 ) break; */
pRight = pExpr->pRight;
if( pRight->op==TK_ID ){
zDb = 0;
zTable = pExpr->pLeft->u.zToken;
zColumn = pRight->u.zToken;
}else{
assert( pRight->op==TK_DOT );
zDb = pExpr->pLeft->u.zToken;
zTable = pRight->pLeft->u.zToken;
zColumn = pRight->pRight->u.zToken;
}
return lookupName(pParse, zDb, zTable, zColumn, pNC, pExpr);
}
/* Resolve function names
*/
case TK_FUNCTION: {
ExprList *pList = pExpr->x.pList; /* The argument list */
int n = pList ? pList->nExpr : 0; /* Number of arguments */
int no_such_func = 0; /* True if no such function exists */
int wrong_num_args = 0; /* True if wrong number of arguments */
int is_agg = 0; /* True if is an aggregate function */
int auth; /* Authorization to use the function */
int nId; /* Number of characters in function name */
const char *zId; /* The function name. */
FuncDef *pDef; /* Information about the function */
u8 enc = ENC(pParse->db); /* The database encoding */
assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
notValidPartIdxWhere(pParse, pNC, "functions");
zId = pExpr->u.zToken;
nId = sqlite3Strlen30(zId);
pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0);
if( pDef==0 ){
pDef = sqlite3FindFunction(pParse->db, zId, nId, -2, enc, 0);
if( pDef==0 ){
no_such_func = 1;
}else{
wrong_num_args = 1;
}
}else{
is_agg = pDef->xFunc==0;
if( pDef->funcFlags & SQLITE_FUNC_UNLIKELY ){
ExprSetProperty(pExpr, EP_Unlikely|EP_Skip);
if( n==2 ){
pExpr->iTable = exprProbability(pList->a[1].pExpr);
if( pExpr->iTable<0 ){
sqlite3ErrorMsg(pParse, "second argument to likelihood() must be a "
"constant between 0.0 and 1.0");
pNC->nErr++;
}
}else{
/* EVIDENCE-OF: R-61304-29449 The unlikely(X) function is equivalent to
** likelihood(X, 0.0625).
** EVIDENCE-OF: R-01283-11636 The unlikely(X) function is short-hand for
** likelihood(X,0.0625). */
pExpr->iTable = 62; /* TUNING: Default 2nd arg to unlikely() is 0.0625 */
}
}
}
#ifndef SQLITE_OMIT_AUTHORIZATION
if( pDef ){
auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0);
if( auth!=SQLITE_OK ){
if( auth==SQLITE_DENY ){
sqlite3ErrorMsg(pParse, "not authorized to use function: %s",
pDef->zName);
pNC->nErr++;
}
pExpr->op = TK_NULL;
return WRC_Prune;
}
if( pDef->funcFlags & SQLITE_FUNC_CONSTANT ) ExprSetProperty(pExpr,EP_Constant);
}
#endif
if( is_agg && (pNC->ncFlags & NC_AllowAgg)==0 ){
sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId);
pNC->nErr++;
is_agg = 0;
}else if( no_such_func && pParse->db->init.busy==0 ){
sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId);
pNC->nErr++;
}else if( wrong_num_args ){
sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()",
nId, zId);
pNC->nErr++;
}
if( is_agg ) pNC->ncFlags &= ~NC_AllowAgg;
sqlite3WalkExprList(pWalker, pList);
if( is_agg ){
NameContext *pNC2 = pNC;
pExpr->op = TK_AGG_FUNCTION;
pExpr->op2 = 0;
while( pNC2 && !sqlite3FunctionUsesThisSrc(pExpr, pNC2->pSrcList) ){
pExpr->op2++;
pNC2 = pNC2->pNext;
}
if( pNC2 ) pNC2->ncFlags |= NC_HasAgg;
pNC->ncFlags |= NC_AllowAgg;
}
/* FIX ME: Compute pExpr->affinity based on the expected return
** type of the function
*/
return WRC_Prune;
}
#ifndef SQLITE_OMIT_SUBQUERY
case TK_SELECT:
case TK_EXISTS: testcase( pExpr->op==TK_EXISTS );
#endif
case TK_IN: {
testcase( pExpr->op==TK_IN );
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
int nRef = pNC->nRef;
notValidCheckConstraint(pParse, pNC, "subqueries");
notValidPartIdxWhere(pParse, pNC, "subqueries");
sqlite3WalkSelect(pWalker, pExpr->x.pSelect);
assert( pNC->nRef>=nRef );
if( nRef!=pNC->nRef ){
ExprSetProperty(pExpr, EP_VarSelect);
}
}
break;
}
case TK_VARIABLE: {
notValidCheckConstraint(pParse, pNC, "parameters");
notValidPartIdxWhere(pParse, pNC, "parameters");
break;
}
}
return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue;
}
/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr
** expression node refer back to that source column. The following changes
** are made to pExpr:
**
** pExpr->iDb Set the index in db->aDb[] of the database X
** (even if X is implied).
** pExpr->iTable Set to the cursor number for the table obtained
** from pSrcList.
** pExpr->pTab Points to the Table structure of X.Y (even if
** X and/or Y are implied.)
** pExpr->iColumn Set to the column number within the table.
** pExpr->op Set to TK_COLUMN.
** pExpr->pLeft Any expression this points to is deleted
** pExpr->pRight Any expression this points to is deleted.
**
** The zDb variable is the name of the database (the "X"). This value may be
** NULL meaning that name is of the form Y.Z or Z. Any available database
** can be used. The zTable variable is the name of the table (the "Y"). This
** value can be NULL if zDb is also NULL. If zTable is NULL it
** means that the form of the name is Z and that columns from any table
** can be used.
**
** If the name cannot be resolved unambiguously, leave an error message
** in pParse and return WRC_Abort. Return WRC_Prune on success.
*/
static int lookupName(
Parse *pParse, /* The parsing context */
const char *zDb, /* Name of the database containing table, or NULL */
const char *zTab, /* Name of table containing column, or NULL */
const char *zCol, /* Name of the column. */
NameContext *pNC, /* The name context used to resolve the name */
Expr *pExpr /* Make this EXPR node point to the selected column */
){
int i, j; /* Loop counters */
int cnt = 0; /* Number of matching column names */
int cntTab = 0; /* Number of matching table names */
int nSubquery = 0; /* How many levels of subquery */
sqlite3 *db = pParse->db; /* The database connection */
struct SrcList_item *pItem; /* Use for looping over pSrcList items */
struct SrcList_item *pMatch = 0; /* The matching pSrcList item */
NameContext *pTopNC = pNC; /* First namecontext in the list */
Schema *pSchema = 0; /* Schema of the expression */
int isTrigger = 0; /* True if resolved to a trigger column */
Table *pTab = 0; /* Table hold the row */
Column *pCol; /* A column of pTab */
assert( pNC ); /* the name context cannot be NULL. */
assert( zCol ); /* The Z in X.Y.Z cannot be NULL */
assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );
/* Initialize the node to no-match */
pExpr->iTable = -1;
pExpr->pTab = 0;
ExprSetVVAProperty(pExpr, EP_NoReduce);
/* Translate the schema name in zDb into a pointer to the corresponding
** schema. If not found, pSchema will remain NULL and nothing will match
** resulting in an appropriate error message toward the end of this routine
*/
if( zDb ){
testcase( pNC->ncFlags & NC_PartIdx );
testcase( pNC->ncFlags & NC_IsCheck );
if( (pNC->ncFlags & (NC_PartIdx|NC_IsCheck))!=0 ){
/* Silently ignore database qualifiers inside CHECK constraints and partial
** indices. Do not raise errors because that might break legacy and
** because it does not hurt anything to just ignore the database name. */
zDb = 0;
}else{
for(i=0; i<db->nDb; i++){
assert( db->aDb[i].zName );
if( sqlite3StrICmp(db->aDb[i].zName,zDb)==0 ){
pSchema = db->aDb[i].pSchema;
break;
}
}
}
}
/* Start at the inner-most context and move outward until a match is found */
while( pNC && cnt==0 ){
ExprList *pEList;
SrcList *pSrcList = pNC->pSrcList;
if( pSrcList ){
for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
pTab = pItem->pTab;
assert( pTab!=0 && pTab->zName!=0 );
assert( pTab->nCol>0 );
if( pItem->pSelect && (pItem->pSelect->selFlags & SF_NestedFrom)!=0 ){
int hit = 0;
pEList = pItem->pSelect->pEList;
for(j=0; j<pEList->nExpr; j++){
if( sqlite3MatchSpanName(pEList->a[j].zSpan, zCol, zTab, zDb) ){
cnt++;
cntTab = 2;
pMatch = pItem;
pExpr->iColumn = j;
hit = 1;
}
}
if( hit || zTab==0 ) continue;
}
if( zDb && pTab->pSchema!=pSchema ){
continue;
}
if( zTab ){
const char *zTabName = pItem->zAlias ? pItem->zAlias : pTab->zName;
assert( zTabName!=0 );
if( sqlite3StrICmp(zTabName, zTab)!=0 ){
continue;
}
}
if( 0==(cntTab++) ){
pMatch = pItem;
}
for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
/* If there has been exactly one prior match and this match
** is for the right-hand table of a NATURAL JOIN or is in a
** USING clause, then skip this match.
*/
if( cnt==1 ){
if( pItem->jointype & JT_NATURAL ) continue;
if( nameInUsingClause(pItem->pUsing, zCol) ) continue;
}
cnt++;
pMatch = pItem;
/* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
pExpr->iColumn = j==pTab->iPKey ? -1 : (i16)j;
break;
}
}
}
if( pMatch ){
pExpr->iTable = pMatch->iCursor;
pExpr->pTab = pMatch->pTab;
pSchema = pExpr->pTab->pSchema;
}
} /* if( pSrcList ) */
#ifndef SQLITE_OMIT_TRIGGER
/* If we have not already resolved the name, then maybe
** it is a new.* or old.* trigger argument reference
*/
if( zDb==0 && zTab!=0 && cntTab==0 && pParse->pTriggerTab!=0 ){
int op = pParse->eTriggerOp;
assert( op==TK_DELETE || op==TK_UPDATE || op==TK_INSERT );
if( op!=TK_DELETE && sqlite3StrICmp("new",zTab) == 0 ){
pExpr->iTable = 1;
pTab = pParse->pTriggerTab;
}else if( op!=TK_INSERT && sqlite3StrICmp("old",zTab)==0 ){
pExpr->iTable = 0;
pTab = pParse->pTriggerTab;
}else{
pTab = 0;
}
if( pTab ){
int iCol;
pSchema = pTab->pSchema;
cntTab++;
for(iCol=0, pCol=pTab->aCol; iCol<pTab->nCol; iCol++, pCol++){
if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
if( iCol==pTab->iPKey ){
iCol = -1;
}
break;
}
}
if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) && HasRowid(pTab) ){
/* IMP: R-24309-18625 */
/* IMP: R-44911-55124 */
iCol = -1;
}
if( iCol<pTab->nCol ){
cnt++;
if( iCol<0 ){
pExpr->affinity = SQLITE_AFF_INTEGER;
}else if( pExpr->iTable==0 ){
testcase( iCol==31 );
testcase( iCol==32 );
pParse->oldmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
}else{
testcase( iCol==31 );
testcase( iCol==32 );
pParse->newmask |= (iCol>=32 ? 0xffffffff : (((u32)1)<<iCol));
}
pExpr->iColumn = (i16)iCol;
pExpr->pTab = pTab;
isTrigger = 1;
}
}
}
#endif /* !defined(SQLITE_OMIT_TRIGGER) */
/*
** Perhaps the name is a reference to the ROWID
*/
if( cnt==0 && cntTab==1 && pMatch && sqlite3IsRowid(zCol)
&& HasRowid(pMatch->pTab) ){
cnt = 1;
pExpr->iColumn = -1; /* IMP: R-44911-55124 */
pExpr->affinity = SQLITE_AFF_INTEGER;
}
/*
** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
** might refer to an result-set alias. This happens, for example, when
** we are resolving names in the WHERE clause of the following command:
**
** SELECT a+b AS x FROM table WHERE x<10;
**
** In cases like this, replace pExpr with a copy of the expression that
** forms the result set entry ("a+b" in the example) and return immediately.
** Note that the expression in the result set should have already been
** resolved by the time the WHERE clause is resolved.
**
** The ability to use an output result-set column in the WHERE, GROUP BY,
** or HAVING clauses, or as part of a larger expression in the ORDRE BY
** clause is not standard SQL. This is a (goofy) SQLite extension, that
** is supported for backwards compatibility only. TO DO: Issue a warning
** on sqlite3_log() whenever the capability is used.
*/
if( (pEList = pNC->pEList)!=0
&& zTab==0
&& cnt==0
){
for(j=0; j<pEList->nExpr; j++){
char *zAs = pEList->a[j].zName;
if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){
Expr *pOrig;
assert( pExpr->pLeft==0 && pExpr->pRight==0 );
assert( pExpr->x.pList==0 );
assert( pExpr->x.pSelect==0 );
pOrig = pEList->a[j].pExpr;
if( (pNC->ncFlags&NC_AllowAgg)==0 && ExprHasProperty(pOrig, EP_Agg) ){
sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs);
return WRC_Abort;
}
resolveAlias(pParse, pEList, j, pExpr, "", nSubquery);
cnt = 1;
pMatch = 0;
assert( zTab==0 && zDb==0 );
goto lookupname_end;
}
}
}
/* Advance to the next name context. The loop will exit when either
** we have a match (cnt>0) or when we run out of name contexts.
*/
if( cnt==0 ){
pNC = pNC->pNext;
nSubquery++;
}
}
/*
** If X and Y are NULL (in other words if only the column name Z is
** supplied) and the value of Z is enclosed in double-quotes, then
** Z is a string literal if it doesn't match any column names. In that
** case, we need to return right away and not make any changes to
** pExpr.
**
** Because no reference was made to outer contexts, the pNC->nRef
** fields are not changed in any context.
*/
if( cnt==0 && zTab==0 && ExprHasProperty(pExpr,EP_DblQuoted) ){
pExpr->op = TK_STRING;
pExpr->pTab = 0;
return WRC_Prune;
}
/*
** cnt==0 means there was not match. cnt>1 means there were two or
** more matches. Either way, we have an error.
*/
if( cnt!=1 ){
const char *zErr;
zErr = cnt==0 ? "no such column" : "ambiguous column name";
if( zDb ){
sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol);
}else if( zTab ){
sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol);
}else{
sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol);
}
pParse->checkSchema = 1;
pTopNC->nErr++;
}
/* If a column from a table in pSrcList is referenced, then record
** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes
** bit 0 to be set. Column 1 sets bit 1. And so forth. If the
** column number is greater than the number of bits in the bitmask
** then set the high-order bit of the bitmask.
*/
if( pExpr->iColumn>=0 && pMatch!=0 ){
int n = pExpr->iColumn;
testcase( n==BMS-1 );
if( n>=BMS ){
n = BMS-1;
}
assert( pMatch->iCursor==pExpr->iTable );
pMatch->colUsed |= ((Bitmask)1)<<n;
}
/* Clean up and return
*/
sqlite3ExprDelete(db, pExpr->pLeft);
pExpr->pLeft = 0;
sqlite3ExprDelete(db, pExpr->pRight);
pExpr->pRight = 0;
pExpr->op = (isTrigger ? TK_TRIGGER : TK_COLUMN);
lookupname_end:
if( cnt==1 ){
assert( pNC!=0 );
if( pExpr->op!=TK_AS ){
sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList);
}
/* Increment the nRef value on all name contexts from TopNC up to
** the point where the name matched. */
for(;;){
assert( pTopNC!=0 );
pTopNC->nRef++;
if( pTopNC==pNC ) break;
pTopNC = pTopNC->pNext;
}
return WRC_Prune;
} else {
return WRC_Abort;
}
}
