Question

I have a table with 2 columns, both having names

I want a query that finds only unique names – names that only appear once max in the entire table.

For example, for the following table:

NAME1    |     NAME2
--------------------
DAN             MIKE
MIKE            TONY
FOO              DAN

It should only return FOO and TONY.

Thanks

Answer 1

I guess you could do it a few ways, but here’s one (assuming Name1 and Name2 are of the same, or implicitly convertible types):

SELECT [Name]
FROM (SELECT Name1 AS [Name] FROM [Table] UNION ALL SELECT Name2 FROM [Table])
GROUP BY [Name]
HAVING COUNT(*) = 1