Based on the ScottPletcher solution from http://www.experts-exchange.com/Microsoft/Development/MS-SQL-Server/Q_24204894.html --SELECT dbo.GetMax(23, 45, 64, 22, 18, 224, 74, 138, 1, 98, 11, 86, 198) --Naturally adjust data type to match what you actually need for your specific values I’ve created a set of functions (e.g. GetMaxOfDates3, GetMaxOfDates13 )to find max of up to 13 Date values. CREATE FUNCTION GetMaxOfDates13 ( @value01 DateTime = NULL, @value02 DateTime = NULL, @value03 DateTime = NULL, @value04 DateTime = NULL, @value05 DateTime = NULL, @value06 DateTime = NULL, @value07 DateTime = NULL, @value08 DateTime = NULL, @value09 DateTime = NULL, @value10 DateTime = NULL, @value11 DateTime = NULL, @value12 DateTime = NULL, @value13 DateTime = NULL ) RETURNS DateTime AS BEGIN RETURN ( SELECT TOP 1 value FROM ( SELECT @value01 AS value UNION ALL SELECT @value02 UNION ALL SELECT @value03 UNION ALL SELECT @value04 UNION ALL SELECT @value05 UNION ALL SELECT @value06 UNION ALL SELECT @value07 UNION ALL SELECT @value08 UNION ALL SELECT @value09 UNION ALL SELECT @value10 UNION ALL SELECT @value11 UNION ALL SELECT @value12 UNION ALL SELECT @value13 ) AS [values] ORDER BY value DESC ) END --FUNCTION GO CREATE FUNCTION GetMaxOfDates3 ( @value01 DateTime = NULL, @value02 DateTime = NULL, @value03 DateTime = NULL ) RETURNS DateTime AS BEGIN RETURN dbo.GetMaxOfDates13(@value01,@value02,@value03,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL) END --FUNCTION
I haven't considered UNPIVOT solution at the time of writing these functions, but it probably will be better.
Other solutions can be found at http://stackoverflow.com/questions/71022/sql-max-of-multiple-columns