<?php $querySol = mysqli_query($connect,"SELECT * FROM Asistentes WHERE acepto = 'on' "); while($dataSol = mysqli_fetch_array($querySol)){ mysqli_query($connect,"UPDATE Asistentes SET update_at = '".$dataSol["created_at"]."' WHERE id = '".$dataSol["id"]."' "); echo $dataSol["created_at"]; echo '<hr>'; } ?>