Here are some examples of how to utilize mysql_error ()
mysql_connect("your.hostaddress.com",
"username", "password") or die(mysql_error()) This will return an error if there is a problem connecting to your MySQL database
$value = mysql_query($your_query)
or die("A MySQL error has occurred.<br />Your Query: " .
$your_query . "<br /> Error:
(" . mysql_errno() . ") " . mysql_error())When you encounter an error, this will return your custom message (A MySQL error has occurred.<br />) followed by a line number, and the actual
thanks http://php.about.com/od/phpwithmysql/f/mysql_error.htm