There are a number of ways to act as a client to a MySQL server from the ctrlX CORE. The question is what do you need the data for?
The IoT Dashboard app, for example, can use MySQL as a data source to create visualizations of the data.
With Node-RED, you can read/write data and utilize it how you wish via javascript (node-red-node-mysql)
You could also write a custom application to access and manipulate a MySQL database. See example below.
