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postgres/src/backend/utils/adt
Tom Lane f68e11f373 Implement subselects in target lists. Also, relax requirement that
subselects can only appear on the righthand side of a binary operator.
That's still true for quantified predicates like x = ANY (SELECT ...),
but a subselect that delivers a single result can now appear anywhere
in an expression.  This is implemented by changing EXPR_SUBLINK sublinks
to represent just the (SELECT ...) expression, without any 'left hand
side' or combining operator --- so they're now more like EXISTS_SUBLINK.
To handle the case of '(x, y, z) = (SELECT ...)', I added a new sublink
type MULTIEXPR_SUBLINK, which acts just like EXPR_SUBLINK used to.
But the grammar will only generate one for a multiple-left-hand-side
row expression.
1999-11-15 02:00:15 +00:00
..
1999-09-21 20:58:25 +00:00
1999-07-15 22:40:16 +00:00