What are some common issues when configuring PHP extensions like php_mysql.dll in the php.ini file?

One common issue when configuring PHP extensions like php_mysql.dll in the php.ini file is specifying the incorrect extension directory. To solve this, ensure that the extension_dir points to the correct directory where the PHP extensions are located. Additionally, make sure that the extension is uncommented in the php.ini file.

extension_dir = "ext"
extension=php_mysql.dll