I'm using Pervasive 2000i SQL with Platinum for Windows. When I try to run the following query, it gets hung up like it is stuck in a loop.

Can anyone tell me what I have done wrong?

SELECT custkey, custname, shipaddr1, invdate, agedate, invno, doctot, reference
FROM "ARHDRH"
where location = 'RAL' and (arhdrh.invno not in (SELECT arhdrh. invno FROM "ARHDRH", "ARTRANH"
where arhdrh.invno = artranh.applytodocno)

How long have you let it run? How many records are in the tables? What's probably happening is a temporary sort file is being created.
How long does the subquery (SELECT arhdrh. invno FROM "ARHDRH", "ARTRANH" where arhdrh.invno = artranh.applytodocno) take?

The subquery itself just takes a few minutes, I left the entire query running while I went to lunch, over an hour and it still hadn't returned anything when I got back. When I go into Windows task manager it says "not responding".