Easiest way to export specific user-generated content?
Views module is the only solution which makes your task very easy. 

1.Simply create a view and add the necessary fields you want to export.

2.Add a display (data export).

3.In DATA EXPORT SETTINGS name your path with .csv extension example data.csv

Finally call the path on your browser. That's it 

Another difficult way is to write queries and then create a php code to export the result to csv