I am using DB2 OS/390 7.1.1.
My question is how do I get the difference between what is in table 'A' and
not in table 'B'?
I have tried using the NOT EXISTS clause without any luck.
QUESTION POSED ON: 07 OCT 2004
QUESTION ANSWERED BY:
Craig Mullins
Well, if you have a primary key in both tables, the answer would be
something like this:
SELECT *
FROM TableA A
WHERE A.KEY NOT IN (SELECT B.KEY FROM TableB B);
Of course, if you do not have keys that match between these tables then
you'd have to figure out if there are duplicate rows, and what that means to
your question. In other words, if you have four exact duplicate rows in
TableA and two in TableB, then is this a match (meaning there is no
difference) or do you want to return two of the four? And what about the
opposite (two in TableA and four in TableB)?
And if there is no key at all, are you wanting to compare every column in
TableA against every column in TableB? That might actually be quicker to
answer by writing a one-off program.
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