如果mysql更新语句执行则返回true，没有更新行时返回false

Question

i have a mysql update statement but it return true when rows are updated and when no row is updated.

i want to knw if row was altered or not.

here is my query:

$q=mysql_query("UPDATE results set marks='$mark' and total='$total'
                 where result_id='$rid'");


if($q){
      echo 'rows updated';
   }
else{
      echo 'No row was updated';
   }

it always print the "row updated " message, whether no record updated or not.

any help plz?

Answer 1

First, the proper syntax is:

UPDATE results
    set marks='$mark', total='$total'
    where result_id='$rid';

You might want to phrase it as:

UPDATE results
    set marks='$mark', total='$total'
    where result_id='$rid' and marks <> '$mark' and total <> '$total';

I think different versions of MySQL differ on whether or not they report a selected row changing, even when the new versions of the values are the same as the old values.