SQL - Ugly combination of GROUP BY and COALESCE

Question

I have a table with data similar to the following:

[ID], [State], [foo], [DateCreated], [DateUpdated]

The longer I work on this, the uglier my SQL is getti

Answer 1

Assuming you are using SQL Server 2005 or >

Try this:

WITH Data AS
(
    SELECT  *,
        COALESCE([DateCreated], [DateUpdated]) AS LastUpdated,
        ROW_NUMBER() OVER(PARTITION BY State ORDER BY COALESCE([DateCreated], [DateUpdated]) DESC) Position
      FROM  a
     WHERE NOT EXISTS
     (
        SELECT  1 
            FROM     b
         WHERE  a.State = b.State
            AND a.foo <> b.foo
     )
)
SELECT State, foo, LastUpdated
  FROM Data
 WHERE Positon = 1