Query for finding groups with no assignee

Query for finding groups with no assignee

Dumb question:

SELECT SERVICE_DESK.call_req.ref_num AS RN
WHERE (SERVICE_DESK.call_req.active_flag = 1) AND (SERVICE_DESK.call_req.group_id = 4554326) AND (SERVICE_DESK.call_req.assignee = '')

I want to find all RNs in a group that are not assigned. This, as shown above does not work...

So I tried these variations that didn't work either:
SERVICE_DESK.call_req.assignee = null;
SERVICE_DESK.call_req.assignee < 'a';
SERVICE_DESK.call_req.assignee LIKE ' %'









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