Mike Mascari <mascarm(at)mascari(dot)com> writes:
> PostgreSQL doesn't index NULLs
Postgres does index NULLs.
However "IS NULL" can't currently use the index, which in this case is
effectively the same thing as they're not being indexed.
However there are other cases like ORDER BY where the fact that Postgres does
index NULLs is important. By comparison Oracle does not index NULLs and as a
result performs differently when doing ORDER BY without a where clause that
excludes NULLs.
--
greg