Subquery (not exists) problem (?)

[Gamb?]

Hello!

I've got some sort of syntax problem that doesn't seem to make a lot
of sense. I'm developing a Categories Theory application and because
of that I need to make big, and by "big" I mean HORRIBLY HUGE queries.
That one has 54 lines and 3 subqueries (only the first one is shown so
that I won't scare people off :)).

The thing is, I don't seem to be getting the hang of how to do
subqueries. The syntax seems fine... But it'll still always say the
same thing:

You have an error in your SQL syntax. Check the manual that
corresponds to your MySQL server version for the right syntax to use
near 'exists ( select * from objeto c, morfismo f1, morfismo f2
(It's MySQL 4.0.11a-gamma)

The only difference I see between the code below and the mysql.com
documentation is that my subqueries aren't alone in their "where"
clauses... Aside from that, they seem pretty much okay. Am I missing
something?

10 · · select o.obj_nome obj, p1.mor_nome pi1, p2.mor_nome pi2
11 · · from objeto o, morfismo p1, morfismo p2
12 · · where
13 · · · o.cat_nome = '$scat' and p1.cat_nome = '$scat' and
p2.cat_nome = '$scat' and
14 · · · p1.obj_dest = '$sa' and
15 · · · p2.obj_dest = '$sb' and
16 · · · p1.obj_orig = o.obj_nome and
17 · · · p2.obj_orig = o.obj_nome and
18 · · · not exists ( select *
19 · · · · from objeto c, morfismo f1, morfismo f2
20 · · · · where
21 · · · · · c.cat_nome = '$scat' and f1.cat_nome = '$scat'
and f2.cat_nome = '$scat' and
·· · · · · · -- (... blah blah blah ...)
63 · · · )

Thank you in advance!

:: =EG= ::