Re: [SQL] query with subquery abnormally slow?

I inadvertently deleted Oskar's message where he described what he is
trying to do at a higher level, but I don't think I'm completely missing
the point with the following:

The table looks like so:

select * from test;
[
ssmldb=> select * from test;
package |artist |song
----------------------+-------------------+-----------------
Surf Comp |Mermen |Pulpin
Surf Comp |Bambi Molesters |Tremor
Surf Comp |The Squares |Squaranoid
Dumb Loud Hollow Twang|Bambi Molesters |Point Break
Dumb Loud Hollow Twang|Bambi Molesters |Glider
Songs of the Cows |Mermen |Songs of the Cows
Surfmania |The Aqua Velvets |Surfmania
Surf Comp 2 |Mermen |Slo Mo H50
Surf Comp 2 |Los Straightjackets|Caveman
]

select t2.* from test t1, test t2
where t1.package = t2.package and
t1.artist = 'Mermen' and t2.artist != 'Mermen';
[
package |artist |song
-----------+-------------------+----------
Surf Comp |Bambi Molesters |Tremor
Surf Comp |The Squares |Squaranoid
Surf Comp 2|Los Straightjackets|Caveman
(3 rows)
]

The query above shows all songs by a different artist that share an album
with a song by the artist in question. It however omits the songs by the
artist in question. To get those back, you could try:

select distinct t1.* from test t1, test t2
where t1.package = t2.package and
((t1.artist = 'Mermen' and t2.artist != 'Mermen') or
(t1.artist != 'Mermen' and t2.artist = 'Mermen'));

or use a union clause:
select t1.* from test t1, test t2
where t1.package = t2.package and
(t2.artist = 'Mermen' and t1.artist != 'Mermen')
union select t3.* from test t3, test t4
where t3.package = t4.package and
(t3.artist = 'Mermen' and t4.artist != 'Mermen') ;

I don't know how these do for speed as I don't care to create a big table
and indices and all that, but they do not use EXITS and it seems with
suitable indices they should be fairly fast.

-Z-