note 90591 added to function.mysql-data-seek

The mysql_query() function using the SELECT, SHOW, DESCRIBE, EXPLAIN or other statements returning a resultset, by default uses a TABLES INDEX, or simply the RECORD INSERT ORDER, in creating the resultset. When using the mysql_data_seek() function along with a mysql_query() function using the SELECT, SHOW, DESCRIBE, EXPLAIN or other statements returning a resultset, and your desire is to SELECT A SPECIFIC ROW based upon the CONTENTS of a SPECIFIC FIELD then be sure to use the ORDER statement in your query or the mysql_data_seek() function may have unpredictable results. Example (Find Last Record): ============================================== <?php $query="SELECT * FROM team ORDER BY team.id ASC"; $result=mysql_query($query); $last_row = mysql_num_rows($result) - 1; if (mysql_data_seek($result, $last_row)) { //Set Pointer To LAST ROW in TEAM table. $row = mysql_fetch_row($result); //Get LAST RECORD in TEAM table $id = $row[0] + 1; //New Team ID Value // more code here ... } else { //Data Seek Error echo "Cannot seek to row $last_row: " . mysql_error() . "\n"; } ?> ============================================== ** Note: 1. The above example code relates to a MYSQL table named 'team' similar to this: +-ID-+ TEAM NAME-+ | 49 | Team 49 | | 33 | Team 33 | | 84 | Team 84 | | 07 | Team 07 | +----+-----------+ ** Records shown in the order inserted (i.e. TABLE NOT INDEXED) 2. In the above example code the field named ID is NOT set to AUTO-INCREMENT (i.e. field value set programmatically). 3. Wanting to insert a new team with a team number higher that the highest team number used, simply using the following code snippet ============================================== <?php $query="SELECT * FROM team"; ?> ============================================== resulted in an ERROR when using the mysql_data_seek() function to select the record with the highest ID value. 4. Use of the ORDER statement in the query corrected the error/problem. Hope this helps someone. ---- Server IP: 69.147.83.197 Probable Submitter: 74.193.232.71 ---- Manual Page -- http://www.php.net/manual/en/function.mysql-data-seek.php Edit -- https://master.php.net/note/edit/90591 Del: integrated -- https://master.php.net/note/delete/90591/integrated Del: useless -- https://master.php.net/note/delete/90591/useless Del: bad code -- https://master.php.net/note/delete/90591/bad+code Del: spam -- https://master.php.net/note/delete/90591/spam Del: non-english -- https://master.php.net/note/delete/90591/non-english Del: in docs -- https://master.php.net/note/delete/90591/in+docs Del: other reasons-- https://master.php.net/note/delete/90591 Reject -- https://master.php.net/note/reject/90591 Search -- https://master.php.net/manage/user-notes.php