Mysql Client无法升级
Mysql从4.0.17升级到4.1.22后，发现Mysql Client无法升级，尝试了多种方法，包括：
升级PHPMyadmin 2.5.4 to 2.8.1 无效
升级PHP， 4.3.4 to 4.4.9 无效
手工覆盖php中libmysql.dll 无效，甚至发觉该DLL根本未被使用。
有两处的信息证实，因为在Windows上的PHP4 Binary版本内置了Mysql Client，那么除非自己重新编译PHP源代码，否则无法仅仅靠下载来升级PHP4所使用的Mysql Client。要想单独升级Mysql Client，要么升级到PHP5，PHP5已经不内置Mysql Client；要么就是在Linux上的安装版本。
1. PHP安装说明文件：
Windows Extensions
;Note that MySQL and ODBC support is now built in, so no dll is needed for it.
2. Mysql.com上的 wiki : http://forge.mysql.com/wiki/PHP_FAQ
PHP4 comes with an old MySQL client statically linked in. You cannot upgrade it without recompiling PHP from source. This is inconvenient, and if you are using PHP on a hosting provider, you probably don’t have privilege to do this.
PHP.net has no plans to release an updated distribution of PHP4 with a newer MySQL client. This issue has been reported several times on bugs.php.net, but they always close the issue with a status of “Bogus”, meaning it’s not a PHP problem.