D. To run the MySQL command, the MySQL module needs to be loaded

Run the above PHP code, the page will be error: Call undefined function

This is because PHP has not yet configured the MySQL module and needs to be configured

One, open the PHP configuration file php.ini, look for "Windows Extensions", find the" PHP Extender area "and find
“; Extension=php_mysql.dll”
“; Extension=php_mysqli.dll"
Remove the semicolon (;) in front of it, and PHP's MySQL module will open
Second, install MySQL, refer to http://jingyan.baidu.com/article/335530daea392519cb41c326.html, after the installation is complete, re-run, you can connect the database properly.

D. To run the MySQL command, the MySQL module needs to be loaded