optimizing sql joins?
From: bugbear <bugbear_at_trim_papermule_trim.co.uk>
Date: Mon, 19 Jul 2004 16:15:48 +0100
Message-ID: <40fbe5a4$0$39746$ed2e19e4_at_ptn-nntp-reader04.plus.net>
I've read (and lost the reference) that when doing joins of this form:
Date: Mon, 19 Jul 2004 16:15:48 +0100
Message-ID: <40fbe5a4$0$39746$ed2e19e4_at_ptn-nntp-reader04.plus.net>
I've read (and lost the reference) that when doing joins of this form:
A.col = B.col and A.col = C.col
It is "helpful" to explicitlty add the
implied join:
B.col = C.col
This is mathematically redundant, but may give the SQL optimiser another (potentially useful/fast) option.
Can anybody comment, (or remember where I might have seen this tip)?
BugBear Received on Mon Jul 19 2004 - 17:15:48 CEST