"Daniel Caune" <[EMAIL PROTECTED]> writes: > Is an index on a nullable column useful for retrieving rows having that > column null?
Nope, because IS NULL isn't an indexable operator. You can make an end-run around that with a partial index, eg create index fooi on foo(f1) where f1 is null This can be used to satisfy queries using "where f1 is null", but it's not any good for any other purpose. If you often do "where f1 is null and something-about-f2", you might get better mileage with create index fooi on foo(f2) where f1 is null but it's still a very specialized index. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings