DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (!isStringOrFixedString(arguments[0])
&& !isArray(arguments[0]))
throw Exception(
"Illegal type " + arguments[0]->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return arguments[0];
}
Columns FunctionArrayIntersect::castColumns(
Block & block, const ColumnNumbers & arguments, const DataTypePtr & return_type,
const DataTypePtr & return_type_with_nulls) const
{
size_t num_args = arguments.size();
Columns columns(num_args);
auto type_array = checkAndGetDataType<DataTypeArray>(return_type.get());
auto & type_nested = type_array->getNestedType();
auto type_not_nullable_nested = removeNullable(type_nested);
const bool is_numeric_or_string = isNumber(type_not_nullable_nested)
|| isDateOrDateTime(type_not_nullable_nested)
|| isStringOrFixedString(type_not_nullable_nested);
DataTypePtr nullable_return_type;
if (is_numeric_or_string)
{
auto type_nullable_nested = makeNullable(type_nested);
nullable_return_type = std::make_shared<DataTypeArray>(type_nullable_nested);
}
const bool nested_is_nullable = type_nested->isNullable();
for (size_t i = 0; i < num_args; ++i)
{
const ColumnWithTypeAndName & arg = block.getByPosition(arguments[i]);
auto & column = columns[i];
if (is_numeric_or_string)
{
/// Cast to Array(T) or Array(Nullable(T)).
if (nested_is_nullable)
{
if (arg.type->equals(*return_type))
column = arg.column;
else
column = castColumn(arg, return_type, context);
}
else
{
/// If result has array type Array(T) still cast Array(Nullable(U)) to Array(Nullable(T))
/// because cannot cast Nullable(T) to T.
if (arg.type->equals(*return_type) || arg.type->equals(*nullable_return_type))
column = arg.column;
else if (static_cast<const DataTypeArray &>(*arg.type).getNestedType()->isNullable())
column = castColumn(arg, nullable_return_type, context);
else
column = castColumn(arg, return_type, context);
}
}
else
{
/// return_type_with_nulls is the most common subtype with possible nullable parts.
if (arg.type->equals(*return_type_with_nulls))
column = arg.column;
else
column = castColumn(arg, return_type_with_nulls, context);
}
}
return columns;
}
