Subject RE: [firebird-support] speed up query
Author sasha
> hi firebird group
> i tried this code
I can't explain it, but if you are using FB 2.0 or above, you might try to
rewrite your second query to not use NOT IN predicate. It might not be
possible of course, because of number of rows in your "Items" table, but you
should check it out.

This is based on release notes under "Existence Predicates NOT IN and ALL
May Be Slow".