Am I missing something here?

You have a query

select * from filePROD
where exists
(select docid from fileFIX
where filePROD.docid = .fileFIX.docid)

which you are running as a Correlated Sub query which forces the operating
system to read through record by record looking for a match.

Couldn't you simply do a

Select docid from FilePROD
Where docid in(Select t1.docid
From FilePROD t1
Inner Join FileFix t2
on t1.DocId = t2.DocId)

The operating system should run the inter query first and get a list of
matches and then run the outer query one by one for the results.

I ran the same thing on my system and ran it through Visual Explain and
that is exactly what it did.

This thread ...


Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2020 by and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].