logging failed queries

Question

I can log all the mysql queries by enabling the general log. But it does not show the failed queries.

Is there a way to save failed queries as well?

Answer 1

You can log ALL queries by setting the sql_log_off variable to 0 (you should have super privilegies)

or you can log failed queries by PHP:

  function sql_query($data)
  {
      $sql = mysql_query($data);
      if($sql == FALSE){
           //do some logging here.
           $fh = fopen("log.txt", 'a') or die("can't open file");
           fwrite($fh, "\n MYSQL ERROR @".microtime(true).": QUERY:".$data."\n");
      }
      return $sql;
  }

Answer 2

It does show failed queries. There is no easy way of segregating them.