Below two functions are very Similar to least and greatest functions in oracle.

1. SQL Code for least: -

GO

/****** Object: UserDefinedFunction [dbo].[least] Script Date: 08/23/2012 00:53:38 ******/

/*Author: Rakesh

Description: This works good for numbers and alphabet.

*/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE function [dbo].[least] (@str1 nvarchar(max),@str2 nvarchar(max))

RETURNS nvarchar(max)

BEGIN

DECLARE @retVal nvarchar(max);

set @retVal = (select case when @str1<=@str2 then @str1 end as retVal)

RETURN @retVal;

END;

GO

Usage: -

select dbo.least(10,100) LEAST_OF_TWO, dbo.least('R','S') LEAST_OF_TWO_ALPHABET

2. SQL code for greatest: -

GO

/****** Object: UserDefinedFunction [dbo].[greatest] Script Date: 08/23/2012 01:00:56 ******/

/*Author: Rakesh

Description: This works good for numbers and alphabet.

*/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

create function [dbo].[greatest] (@str1 nvarchar(max),@str2 nvarchar(max))

RETURNS nvarchar(max)

BEGIN

DECLARE @retVal nvarchar(max);

set @retVal = (select case when @str1<=@str2 then @str2 end as retVal)

RETURN @retVal;

END;

GO

Usage: -

select dbo.greatest(10,100) GREATEST_OF_TWO, dbo.greatest('a','z') GREATEST_OF_TWO_ALPHABET