Any Function in T-SQL thats similar to GREATEST() IN Orcl.

Question

Is there any Function in T-SQL thats similar to GREATEST() IN Orcl?
Iam trying to find the greatest of two DATETIME datatype Fields in my 'select's.
If there is no in built function, Whats the best approach?

Answer 1

MKR,
If you are using SS 2005, you could use the new operator UNPIVOT.
Code Block
DECLARE @MyTable table
( RowID int IDENTITY,
Date1 datetime,
Date2 datetime,
Date3 datetime NOT NULL DEFAULT getdate()
INSERT INTO @MyTable VALUES ( '2007/01/01', '2007/02/01', '2007/01/31' )
INSERT INTO @MyTable VALUES ( '2007/10/10', '2007/11/01', DEFAULT )
INSERT INTO @MyTable VALUES ( '2007/12/01', '2007/12/05', '2007/12/06' )
SELECT
a
.RowID,
a.Date1,
a.Date2,
a.Date3,
b.Greatest
FROM
@MyTable
AS a
INNER JOIN
SELECT
RowID
MAX([Value]) AS Greatest
FROM
@MyTable
UNPIVOT
[Value]
FOR ColumnName IN ([Date1], [Date2], [Date3])
) AS unpvt
GROUP BY
RowID
) AS b
ON a.RowID = b.RowID
ORDER BY
a
.RowID
-- OR
SELECT
a
.*, b.Greatest
FROM
@MyTable
AS a
CROSS APPLY
SELECT
MAX(Value) AS Greatest
FROM
@MyTable
UNPIVOT
[Value]
FOR ColumnName IN ([Date1], [Date2], [Date3])
) AS unpvt
WHERE
unpvt
.RowID = a.RowID
) AS b
ORDER BY
a
.RowID
GO
AMB