SELECT …. WHERE id is in pool of ids of subquery……

I am reading the docu and am looking for an example our explanation as to the difference of setof and arrays.

But maybe this is not even relevant. The reason I am looking for this is because I need to build a function that looks for all records whose ids are in a pool of other records.

Maybe this is not making any sense....

So, here is my function:

1
2

SELECT DISTINCT messages.id FROM messages
JOIN message_recipients msgrec ON msgrec.refid_messages=messages.id AND (msgrec.refid_qmusers=$1 OR messages.refid_sender=$1)

It returns all the IDs of messages of which a given user, the input arg refid_userid, is either a recipient or a sender.

This works as expected.

Now I'd like to get the messages for these ids, but it doesn't work.

It should be something like

SELECT * FROM messages WHERE ID EXISTS (SELECT defect_usermessageids(2))

But this doesn't work.

Please, can someone enlighten me?

Thanks and regards

Alex