Scott Marlowe wrote:
On Sat, 2004-10-02 at 09:14, Stephan Szabo wrote:
On Fri, 1 Oct 2004, Scott Marlowe wrote:
On Fri, 2004-10-01 at 14:26, Shane | SkinnyCorp wrote:
Okay, just so no one posts about this again...
the 'ORDER BY t.status=5,lastreply' clause is meant to float the threads
with a status of '5' to the top of the list... it is NOT meant to only grab
threads where the status = 5. Oh and believe me, when I take this out of
the query, it CERTAINLY doesn't add any more than possible 1/4 of a
millesecond to the speed of the SELECT statement.
Wouldn't this work just as well?
SELECT * FROM thread_listing AS t ORDER BY t.status
DESC,t.lastreply desc LIMIT 25 OFFSET 0
Probably not, because I don't think he wants the other statuses to have
special ranking over the others, so a status=4 and status=1 row should be
sorted by lastreply only effectively. This is the problem of combining
separate status flags into a single field if you want to be doing these
sorts of queries.
So would a union give good performance? Just union the first 25 or less
with status=5 with the rest, using a 1 and 0 in each union to order by
first? Hopefully the indexes would then be used.
anyone seen that the OP is running the server with sequential scan disabled ?
Reagards
Gaetano Mendola
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