- substr: documentation ( source)
- strrpos: documentation ( source)
- strtolower: documentation ( source)
<?php
$sql1=$sql2 = "SELECT assignment_activities.* FROM (assignment_activities) WHERE `iAssignmentId` = '1' ORDER BY assignment_activities.iAssignmentActivityId DESC LIMIT 10";
echo substr($sql1, 0, strrpos(strtolower($sql2), "limit"));