How do you return 1 value per row of the max of several columns:
TableName
[Number, Date1, Date2, Date3, Cost]
I n
Using CROSS APPLY (for 2005+) ....
SELECT MostRecentDate FROM SourceTable CROSS APPLY (SELECT MAX(d) MostRecentDate FROM (VALUES (Date1), (Date2), (Date3)) AS a(d)) md