Question

environment: microsoft sql server 2005, 2008

given:

IF object_id('tempdb..#MyTempTable') IS NOT NULL
BEGIN
   DROP TABLE #MyTempTable
END

CREATE TABLE #MyTempTable
(
   ID int IDENTITY(1,1)
   , date1 datetime
   , date2 datetime
   , date3 datetime
)
INSERT INTO #MyTempTable
SELECT '3/1/2012','3/2/2012',NULL

table datetest
id,date1,date2,date3
------------------------
1, 3/1/2012,3/2/2012,null
2, 3/1/2012,null,null

all 3 dates can be null and up to 3 dates can be entered.

how do you get the most recent date?

for example, if date1 and date2 were filled out for a row, how would you get the most recent date of the 2 columns for that row?

Answer 1

This works for SQL server 2008

DECLARE @MyTempTable
 TABLE (
   ID int IDENTITY(1,1)
   , date1 datetime
   , date2 datetime
   , date3 datetime
)

INSERT INTO @MyTempTable 
SELECT '3/1/2012','3/2/2012',NULL

SELECT [id], (SELECT Max(Dt) FROM (VALUES (date1),(date2),(date3)) AS value(Dt)) as [RecentDate]
FROM @MyTempTable