$query = "UPDATE activities SET (";
	 $append = 0;
	 if ($p_task <> $org['task_id']) {
        $query .="  task_id = {$p_task}";
		$append = 1;
	 }
	 if ($p_assg <> $org['assigned_id']) {
		if ($append) : $query .= ", ";  $append = 0; endif;
        $query .="assigned_id = {$p_assg}";
		$append = 1; 
	 }
	 if ($p_due <> $org['due_date']) {
		if ($append) : $query .= ", ";  $append = 0; endif;
        $query .="due_date = {$p_due}";
		$append = 1; 
	 }
	 if ($p_done <> $org['completed']) {
		if ($append) : $query .= ", ";  $append = 0; endif;
        $query .="completed = {$p_done}";
		$append = 1; 
	 }
     $query .=") WHERE id = {$activity['id']};";