IN vs. EXISTS

From: <Rick_Cale_at_teamhealth.com>
Date: Fri, 18 Oct 2002 10:31:49 -0800
Message-ID: <F001.004EDAB7.20021018103149@fatcity.com>

Hi All,

I have 2 tables

BIG - 100 million records
SMALL - 1 million records.

I want to delete all the records in BIG that are in small. There is a PK on field1.
Which of the below methods would you choose and why?

DELETE FROM big
WHERE field1 IN (SELECT field1 FROM small);

DELETE FROM big a
WHERE EXISTS (SELECT 1 FROM small B

                                    WHERE b.field1 = a.field1);

Thanks
Rick

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  INET: Rick_Cale_at_teamhealth.com

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