Ben,
----- Original Message ----- From: "Ben Dinnerville" Sent: Monday, April 19, 2004 1:49 AM Subject: RE: Slow Query Question - Need help of Gurus. <snip> >>Then try again: >> >> SELECT `Call Svc Tag ID`, >> Count(*) as counter, >> `Journal Create Date` >> FROM 31909_859552 >> WHERE `Journal Create Date` between '2004-03-13' AND '2004-03-16' >> AND `Call Svc Tag ID`<>'null' >> GROUP BY `Call Svc Tag ID` >> HAVING counter > 3 >> ORDER BY counter; > The "count(*)" will be causing some havoc here, as all columns in the > underlying table(s) will have to be read in, negating any direct hits to the > index's and causing a lot more IO than is needed. Change it to a count on > one of the columns in the result set or simply a "count(1) as counter" - > will give you the same result without any IO. COUNT(*) is not a problem. It won't cause the data file to be read if just the index can be used. EXPLAIN will show the same plan for COUNT(*) and COUNT(1). :-) Matt -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
