php man page for mysql_errno

MYSQL_ERRNO(3)								 1							    MYSQL_ERRNO(3)

mysql_errno - Returns the numerical value of the error message from previous MySQL operation

SYNOPSIS
       Warning

	      This  extension  is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should
	      be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:

		     omysqli_errno(3)

		     o PDO::errorCode

       int mysql_errno ([resource  $link_identifier = NULL])

DESCRIPTION
	Returns the error number from the last MySQL function.

	Errors coming back from the MySQL database backend no longer issue warnings. Instead, use mysql_errno(3) 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(3) and
       mysql_errno(3)), so if you want to use it, make sure you check the value before calling another MySQL function.

	      o $
		link_identifier -The MySQL connection. If the link identifier is not specified,  the  last  link  opened  by  mysql_connect(3)	is
		assumed. If no such link is found, it will try to create one as if mysql_connect(3) was called with no arguments. If no connection
		is found or established, an E_WARNING level error is generated.

	Returns the error number from the last MySQL function, or 0 (zero) if no error occurred.

       Example #1

	      mysql_errno(3) example

	      <?php
	      $link = mysql_connect("localhost", "mysql_user", "mysql_password");

	      if (!mysql_select_db("nonexistentdb", $link)) {
		  echo mysql_errno($link) . ": " . mysql_error($link). "
";
	      }

	      mysql_select_db("kossu", $link);
	      if (!mysql_query("SELECT * FROM nonexistenttable", $link)) {
		  echo mysql_errno($link) . ": " . mysql_error($link) . "
";
	      }
	      ?>

	      The above example will output something similar to:

	      1049: Unknown database 'nonexistentdb'
	      1146: Table 'kossu.nonexistenttable' doesn't exist

       mysql_error(3), MySQL error codes.

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