อยากถามเรื่องการ delete ข้อมูลใน db แบบมีเงื่อนไขค่ะ

mysql_query( "update table_A set p_id=$_GET['new_id'] where p_id=$_GET[old_id] "); 
 
if( $_GET['new_id'] != $_GET['old_id']){
  mysql_query( "delete from table_B where p_id=$_GET[old_id] ");
}

$rs=mysql_query("select p_id from table_A where pk_id=$_GET[pk_id] ");
list( $old_p_id)=mysql_fetch_row($rs);

mysql_query("update table_A set p_id=$_GET['p_id'] where pk_id=$_GET[pk_id] " );
 
if( $_GET['p_id'] != $old_p_id ){
 mysql_query( 'delete from table_B where p_id=$old_p_id " );
}