8.14 <type predicate> to be exact.
8.18 in SQL200x. I don't think the current implementation quite meets the spec however:
regression=# select f2 is null, f2 is of(int) from bar; ?column? | ?column? ----------+---------- f | t t | t (2 rows)
If I read the spec correctly, the null value should return null, not 't' in the above.
General Rules 1) Let V be the result of evaluating the <row value predicand>. 2) Let ST be the set consisting of every type that is either some exclusively specified type, or a subtype of some inclusively specified type. 3) Let TPR be the result of evaluating the <type predicate>.
Case: a) If V is the null value, then TPR is Unknown. b) If the most specific type of V is a member of ST, then TPR is True . c) Otherwise, TPR is False
Probably best not to document it until someone gets around to fixing it -- I can do it, but not for the next few weeks at least.
Joe
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