note 59718 added to function.mysql-insert-id

If you insert a data row by using the ON DUPLICATE KEY UPDATE clause in an INSERT-statement, the mysql_insert_id() function will return not the same results as if you directly use LAST_INSERT_ID() in MySQL. See the following example: <? // insert a datarow, primary key is auto_increment // value is a unique key $query = "INSERT INTO test (value) VALUES ('test')"; mysql_query( $query ); echo 'LAST_INSERT_ID: ', mysql_query( "SELECT LAST_INSERT_ID()" ), '<br>mysql_insert_id: ', mysql_insert_id(); ?> This will print: LAST_INSERT_ID: 1 mysql_insert_id: 1 In this case the function returns the same as the MySQL-Statement. But see the insert on an existing key: <? $query = "INSERT INTO test (value) VALUES ('test') ON DUPLICATE KEY UPDATE value = 'test2'"; mysql_query( $query ); echo 'LAST_INSERT_ID: ', mysql_query( "SELECT LAST_INSERT_ID()" ), '<br>mysql_insert_id: ', mysql_insert_id(); ?> This will print: LAST_INSERT_ID: 2 mysql_insert_id: 1 By using the ON DUPLICATE KEY UPDATE clause, only the old datarow will be modified, if the INSERT statement causes a duplicate entry, but the LAST_INSERT_ID() function returns the next auto_increment value for the primary key, which is by the way not set as the next auto_increment value in the database. The mysql_insert_id() function returns the primary key of the old (and changed) data row. For me this is the right operation method, because the LAST_INSERT_ID() function returns a value which is not referenced to a data row at all. Greets from Munich. heiligkind ---- Manual Page -- http://www.php.net/manual/en/function.mysql-insert-id.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+59718 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes&reason=non-english Delete: already in docs -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes&reason=already+in+docs Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+59718&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+59718&report=yes Search -- http://master.php.net/manage/user-notes.php