You should create a PHP page to interact with your MYSQL database. You PHP page runs on your webserver which will accept a HTTP GET command from the PLC.
The PLC connects to the webserver using the <TCPCONNECT> method. Once connected, the PLC will use the PRINT #4 command to send the "GET /xxxx.php?[parameters]" where xxxx.php is the file name of your PLC program and [parameters] are a string of key/value pairs that you pass to your PHP program. The PHP program will then extract the keys and the values from the parameter list and insert them into the MYSQL database records.
If all these are new to you - please hire or consult someone who knows how to write PHP and interact with the MYSQL database as these are beyond the PLC tech support.