SQL challenge;-)

From: Frank an der Heiden <fh_at_energotec.de>
Date: Thu, 3 May 2001 00:20:01 +0200
Message-ID: <9cq15i$e56$1@oxygen.technet.net>

hi,

here a little task for all sql-freaks ;-))

i have to tables.
these tables have the same structure.
i want to check out which row of <column> of the first table is not existing in <column> of the second table.

this sql-statement works:

SELECT <column> FROM <table1> WHERE <column> NOT IN (SELECT <column> FROM <table2>);

but it is very very slow, because the second select is done very often if you have many rows in table1.
any simple idea for improving performance? a tried to use a join, but i wasn't able to bring it to work, maybe it's too late ;-((

good night
frank Received on Wed May 02 2001 - 17:20:01 CDT