unknown result resource with mysql_num_rows

[The1corrupted]

Okay, this has blown my entire perception of reality way out of order. First, a page was working and not five minutes later, I get this error,


Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in C:\Vardaes\gendisp.php on line 66

and I made insignificant changes to the script before hand that had nothing to do with mysql_num_rows();...

Here's line 66
[PHP]
$saynum=mysql_num_rows(mysql_query("SELECT `cn` FROM `user_table` WHERE `cn`='$mesgread[2]' AND `ns`=$x AND `ew`=$y AND `ud`=$z"));
[/PHP]

[ronverdonk]

When the select fails for whatever reason you do not get an object to query the no of rows. So it is better to run the query first and capture the errors and only then get the row count. Like this:

$res = mysql_query("SELECT `cn` FROM `user_table` 
                    WHERE cn`='$mesgread[2]' 
                    AND `ns`=$x 
                    AND `ew`=$y 
                    AND `ud`=$z");
   or die ("Select error: ".mysql_error());
$saynum=mysql_num_rows($res); 

Ronald :cool:

[The1corrupted]

Thanks, and I've found the errors so everything's working fine now.

[ronverdonk]

You are welcome any time.

Ronald :cool: