Yes. It is interesting to have integration with datasourses (ie external tables). I'm thinking of how it can be done flexible.
I think I'll add it in nearest future in 2 parts.
The first - just allow enter SQL to get data and visualize it.
The second - create query builder for easy use to users, how don't know SQL.
I did first part (of 3) and tomorrow will do release and add into documentation examples.
Now I can process SQL datasource and create paths (Lines, Polygons and Circles).
The second step - create placemarks from SQL datasource (I think it is not too hard, I think one day).
And after that I'll take a pause in this part of development, because create manual definition WHERE clause as you show on your image it is not easy, and I want implement the other features.
Ie you can easy create SELECT statement (for example in phpMyAdmin), then copy-paste into my data source and create structure definition. After that use this data source in paths definition (path type will be manage result visualization type). I'll post examples in documentation tomorrow.