I'm seeing another problem in the Search plugin even without this PR applied. If no custom fields are defined in com_content nothing is returned when doing a search.

@ralain did you proof that or is it only an assumption?

@laoneo Stumbled on it by accident during fields/search testing, not an assumption. With the custom field my test article would be returned from the search. Without the a field, or with the field unpublished, it would not.

I'v deleted all my fields and made sure that all fields tables are empty. Then I created an article with demo in the title. When I search in the default search module for demo, then the article shows up. If there is really a bug please open a new issue and prefix it with [com_fields]. Thanks.

I might be mistaken, will check again tonight.

should be another issue related to non-mysql DB, i'll investigate on it...

Thank you guys for taking so much care of Postgres and MSSql implementation, really appreciated!

I have tested this item ✅ successfully on 7f4a852

Tested on MySQL and PostgreSQL. I assume MSSQL still has problems, but it wouldn't be because of this PR.

If #13302 and #13348 are merged, we don't have a need anymore for this PR (at least not in core).

yes....,
after merge, i'll redo to only add the postgresql translation for GROUP_CONCAT()

Both my PRs are merged now. So no GROUP_CONCAT is used anymore in core to my knowledge.
So do we still want to add this here or do we just close it? We're still missing the implementation or MSSQL anyway.

ok, i'm closing this one
but i'll open a new one cause maybe some 3dp extensions could use it