Code Spatter - Latest Comments in MySQL Fun

Re: MySQL Fun

Greg Allard — Fri, 18 Jan 2008 01:06:55 -0000

After all the fighting to get this to a better table schema, it increased the query I was trying to optimize from 23.0878 seconds to 0.0638 seconds. That's like 36,000% better!

Re: MySQL Fun

Greg Allard — Fri, 18 Jan 2008 01:06:36 -0000

Left the limit out even though I thought it wouldn't be able to do it, but it went through.

Affected rows: 4176 (Query took 176.0788 sec)

Re: MySQL Fun

Greg Allard — Fri, 18 Jan 2008 01:06:17 -0000

I'm doing this

UPDATE tbd_requests
SET request_taken_time =
(
SELECT history_created
FROM tbd_history
WHERE tbd_history.request_id = tbd_requests.request_id
AND history_action LIKE 'taken'
ORDER BY history_created DESC
LIMIT 0, 1
)
WHERE request_type != 11
ORDER BY request_id ASC
LIMIT 0, 1

and getting this

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' 1' at line 13

Fate doesn't want to allow me to restructure this database, it wants me to forever have slow queries.

Re: MySQL Fun

Greg Allard — Fri, 18 Jan 2008 01:05:51 -0000

I think I might need to do some nested query where I set request_taken_time = (SELECT history_created order by blah blah) That may be the only way to get it to work accurately, however it will be slow since it doesn't seem to do nested queries efficiently