10

How do I detect errors when using $wpdb->get_results()?

For example:

$result = $wpdb->get_results("SELECT * FROM this is not a valid query");

The preceding code doesn't generate any exceptions or errors; it simply sets $result to an empty array. How do we reliably detect errors generated by get_results()?

10

There is a class variable that stores the last error string - $wpdb->last_error. By the looks of the way $wpdb is coded, if the query succeeds, $wpdb->last_error will be an empty string, if it fails, it will be the error string returned by MySQL. So something like this would do the trick.

$result = $wpdb->get_results("SELECT * FROM this is not a valid query");
if ($wpdb->last_error) {
  echo 'You done bad! ' . $wpdb->last_error;
}
2
  • Sounds reasonable - I can't look into this right now, but if this works, it would come in handy in the future! Thanks! :)
    – rinogo
    Apr 23 '15 at 16:49
  • Came back to this on a later assignment - works great! I've put this code into a function; I updated your answer; I hope you don't mind!
    – rinogo
    Nov 6 '17 at 18:53
1

The best I can find is:

$wpdb->show_errors();
$result = $wpdb->get_results("SELECT * FROM this is not a valid query");
$wpdb->hide_errors();

Unfortunately, that hardly solves the problem. I want to handle the error programmatically, not just echo it to the output stream.

1
  • I suppose I could always do something nasty with intercepting the output buffer... :/
    – rinogo
    Apr 17 '14 at 22:01

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