sql - Compare columns but exclude specific pairs

Question

I want to write query to compare columns between two tables but to exclude specific pairs which point to the same thing but are written differently.

ID	Name
1	NYSE
2	OTC
3	OTC

Answer 1

If you have some kind of lookup table, you could use a NOT EXISTS to check the value isn't in the other table:

SELECT ST.[Name]
FROM dbo.SecondTable ST
WHERE NOT EXISTS (SELECT 1
                  FROM dbo.LookupTable LT
                       JOIN dbo.FirstTable FT ON LT.FirstTableID = FT.ID
                  WHERE LT.SecondTableID = ST.ID);