Re: finding unmatched values from two columns

[David Shrewsbury]

First of all, I'm sure it's a typo, but those commas in the WHERE clause should be periods. :-)

Second, what you are looking for is an outer join. To find rows in t1 that are not in t2, try this:

SELECT t1.c1
FROM t1 LEFT JOIN t2 ON t1.c1 = t2.c2
WHERE t2.c2 IS NULL;

You can find more information (albeit a bit wordy) on the JOIN syntax here: http://dev.mysql.com/doc/refman/5.0/en/join.html

-Dave



Edited 1 time(s). Last edit at 09/20/2006 08:17AM by David Shrewsbury.