I want my query to bring back one set of results based on a priority value (a,b,c or d).
(all other values sought are standard across all records, which means the only differentiator is the priority column).

Basically bring me back priority 'c' if it is there and if not, bring me back priority 'b'

I think I can only make priority 'c' come back as NULL, if I use a union all query structure. Should that be what I do or is there a more efficient CASE statement , for example.