Re: Query Question
From: John Gillespie <jgg_at_waldo.corte-madera.geoquest.slb.com>
Date: 30 Jul 1994 00:09:30 GMT
Message-ID: <31c5nq$v4_at_k2.San-Jose.ate.slb.com>
Date: 30 Jul 1994 00:09:30 GMT
Message-ID: <31c5nq$v4_at_k2.San-Jose.ate.slb.com>
In article <31c10k$4sa_at_sun.cais.com>, sarek_at_cais2.cais.com (Scott T Johnson) writes:
|> I have a preformance problem. I have two tables: A & B. I need to update
|> A from B based on whats already in A.
|> A B
|> 2 1
|> 4 2
|> 3
|> 4
|> 5
|>
|> I need table A to have the same values as B. Values 2 and 4
|> cannot be deleted or duplicated. I tried: INSERT INTO A SELECT C1 FROM B
|> WHERE C1 NOT IN (SELECT C1 FROM B); This takes forever!! Help!!
|>
|> Thanks,
|> Scott
|>
|>
|>
|> --- -----
|>
|>
Try this:
INSERT INTO A
SELECT C1 FROM B WHERE NOT EXISTS
(SELECT NULL FROM A WHERE A.C1=B.C1)
Received on Sat Jul 30 1994 - 02:09:30 CEST