mysql ise php 7 de çalışmaz kodları mysqli ye çevirmeniz gerekiyor.
php 5.6 sürümünde çalışıyorsa eğer, mysql kullanamaz.
Warning
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. 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:
mysqli_connect()
PDO::__construct()
Kaynak: https://www.php.net/manual/en/function.mysql-connect.php