Is there a feature to group by type strings?
I don't understand what are asking for. Can you describe it in more details.
And please include "Diagnostic Info" from Admin > Troubleshooting, and which database type you are querying or having problems with.
I am using postgres. I mean like the postgres string_agg to use in "custom question".
@Gabriele You would have to use Native queries (SQL) for that.