SELECT CONCAT_WS('','
    <form action="./assigntask.php" id="assign_form" method="post"><input type="hidden" name="id" value="',in_id,'"><input type="text" name="due_date" id="tasks_due_date',in_id,'" value="',IF(declare_due_date='0000-00-00','',declare_due_date),'" class="date ',IF(MOD(in_row,2)=1,'EVEN','ODD'),'"></form>
') INTO return_value;