If you are trying to get information about EmployeeNmbr 2 who is in Sales department, then you could do this:
col1,col2, col3 -- etc. replace with actual column names
Department = 'Sales'
and EmployeeNmbr = @EmployeeNmbr_Variable;
Then, you can check if it returned any rows at all using @@ROWCOUNT as in
if (@@ROWCOUNT = 0) print 'No such employee in Sales!';
Now, I may not have understood your requirement exactly - especially since you say: "This would work, if the query resulted in a single record, but it doesn't...". So if this is not what you are looking for, can you give more information?