Hi John, You can't use aggregate function in the WHERE clause, because they aren't evaluated until after the WHERE clause is applied.
Wouldn't it be much easier to simply keep a last_tweet_date field updated somewhere then simply do SELECT USER_NAME FROM USERS WHERE last_tweet_date < NOW()-INTERVAL 7 DAY; ? Regards, Gavin Towey -----Original Message----- From: John Meyer [mailto:johnme...@pueblocomputing.com] Sent: Wednesday, September 16, 2009 12:52 PM To: mysql@lists.mysql.com Subject: Datediff function I'm trying to pull up a list of users who haven't tweeted in 7 or more days, and I'm trying to use this statement: SELECT USER_NAME, MAX(TWEET_CREATEDAT) FROM USERS NATURAL JOIN TWEETS WHERE DATEDIFF(NOW(),MAX(TWEET_CREATEDAT)) > 7 GROUP BY USERS.USER_ID But it says "invalid group function". How should I reword this query? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=gto...@ffn.com The information contained in this transmission may contain privileged and confidential information. It is intended only for the use of the person(s) named above. If you are not the intended recipient, you are hereby notified that any review, dissemination, distribution or duplication of this communication is strictly prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
