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-