Hello HPPraxis.

Thank you for your purchase.

Adding a new column from the plugin's side is impossible when you're dealing with SQL Query based tables. Those tables are using the SQL tables as an existing data source (just like Excel or CSV), but they can be edited unlike Excel and CSV. You can't, however, add new columns from wpDataTables, only in PHPMyAdmin.

I see what you're talking about, though - in our documentation, when the tables are created from "Employees", "Shippers" and "Customers" the screenshots below are showing the remove and add  buttons. But I can confirm that it is not possible to achieve through version 2.0; 2.3.2; 2.4 and 2.5. I can't say that the feature wasn't there when the documentation was written (which can be on a much older version of the plugin), but I seriously doubt that.

A different part of our documentation, which talks about back-end-editor says that the "Add new column" and "Delete column" buttons are specific for manual tables. They cannot be present in the SQL Query based tables.

So, with this in mind - if you would like to add new columns - you can add them in PHPMyAdmin, and they'll be shown in the plugin. Or you can create a new manual table, where you'd need to define every column.

Best regards.