Re: problems with mysql_query() and mysql_num_rows()

mysql_num_rows() will only work if there were any rows returned from the SQL statement. Like this: $res = mysql_db_query("database", " some SQL statement"); $nrows = mysql_num_rows($res); this will only work if $res contains a valid SQL set. It doesnt really have to do with whether its true or not. How could mysql_num_rows work on a true/false scale? what you should do is this: $res = mysql_db_query("database", " some SQL statement"); if( mysql_errno() ) { $err = mysql_error(); echo "$err"; } if (! mysql_errno()) $num_rows = mysql_num_rows($res); by putting in that error-checking statement you can see why your SQL statement is failing, hence the failure of mysql_num_rows(); /Cody Jeffrey A Schoolcraft wrote: > I'm using some code off of webmonkey to do user validation with a mysql > database. They use mysql_num_rows to make sure the result set wasn't 0. > PHP is complaining: > > Warning: Supplied argument is not a valid MySQL result resource in > /usr/local/apache/htdocs/auth.php on line 48 > > And it authorizes everyone. > > So I did some research and set mysql_query() equal to a value, and then > tried to do if (mysql_query()) assuming a false value means it won't > validate, but that didn't work either. > > I'd appreciate any help. > > Jeffrey Schoolcraft