Ok..thanks! But my problem here is how to check if there were any matched rows when no rows were changed. mysql_affected_rows() will tell me the affected rows. Simmly, is there any routine using which one can know if there were any matched rows?
Cheers, Rajan On 6/11/07, ViSolve DB Team <[EMAIL PROTECTED]> wrote:
Hi AFAIK, before changing data, the old values are saved in the rollback segment. On saving the updated values, from the Buffer to the rollback segment/data files, --- it checks if there is any matched row that matches the condition. If found, then flags "Matched". ---after filtering out the matched row, it check whether there is need to change the old value to new value. if need then flags "Changed" and rewrite the same in the datafile/rollback segment. Thanks ViSolve DB Team. ----- Original Message ----- From: "Ace" <[EMAIL PROTECTED]> To: <mysql@lists.mysql.com> Sent: Monday, June 11, 2007 11:41 AM Subject: how to get Number of rows matched? > Hi Experts, > > When issuing updates in mysql (in the console window), mysql will tell > you if any rows matched and how many rows were updated (see below). I > know how to get number of rows udpated using mysql_affected_rows(), but is > there any > way to get the number of rows matched? I want to find out, when rows > updated = 0, if there were no updates because the row wasn't found > (rows matched will = 0) or because the update would not have changed > any data (rows matched = 1). > > mysql> select * from test; > +------+------+ > | roll | s | > +------+------+ > | 1 | new | > +------+------+ > 1 row in set (0.00 sec) > > mysql> update test set roll = 1, s = 'new' where roll = 1; > Query OK, 0 rows affected (0.00 sec) > Rows matched: 1 Changed: 0 Warnings: 0 > > mysql> update test set roll = 1, s = 'new' where roll = 17; > Query OK, 0 rows affected (0.00 sec) > Rows matched: 0 Changed: 0 Warnings: 0 > > mysql> update test set roll = 1, s = 'neww' where roll = 1; > Query OK, 1 row affected (0.00 sec) > Rows matched: 1 Changed: 1 Warnings: 0 > > -- > Cheers, > Rajan > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.472 / Virus Database: 269.8.13/843 - Release Date: 6/10/2007 1:39 PM
