Re: Select .... where id not in (....) returns 0 incorrectly

[Jeremy Smith <jeremy@xxxxxxxxxxxxxx>]

Doesn't this usually happen if q.id contains NULL.  That is as per ANSI
standard.

Yes, there's a good description of this here:

https://wiki.postgresql.org/wiki/Don't_Do_This#Don.27t_use_NOT_IN 

It would be better to use NOT EXISTS:

select count(*) from snapshotlist where NOT EXISTS (SELECT FROM q WHERE q.id = snapshotlist.id);

-Jeremy