(PHP 3, PHP 4 , PHP 5)
mysql_errno -- Returns the numerical value of the error message from previous MySQL operationReturns the error number from the last MySQL function, or 0 (zero) if no error occurred.
Errors coming back from the MySQL database backend no longer issue warnings. Instead, use mysql_errno() to retrieve the error code. Note that this function only returns the error code from the most recently executed MySQL function (not including mysql_error() and mysql_errno()), so if you want to use it, make sure you check the value before calling another MySQL function.
Note: If the optional argument is specified the given link is used to retrieve the error code. If not, the last opened link is used.
See also mysql_error() and MySQL error codes.