A SQL Server, scalar-value function that returns the lesser of two dates.

lesser

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
GO

/*----------------------------------------------------------------------------------------------------
Author:        Craig Buchanan
Date:        2/6/2006
Description:    Returns the lesser of two dates
Parameters:    
  @Date1 - datetime to be compared
  @Date2 - datetime to be compared
----------------------------------------------------------------------------------------------------*/

CREATE FUNCTION [dbo].[MinimumDate] (
  @Date1    datetime,
  @Date2    datetime
)

RETURNS datetime AS

BEGIN

  RETURN CASE
    WHEN @Date1 IS NULL AND @Date2 IS NULL THEN NULL
    WHEN @Date1 IS NULL THEN @Date2
    WHEN @Date2 IS NULL THEN @Date1
    WHEN @Date1 < @Date2 THEN @Date1
    WHEN @Date2 < @Date1 THEN @Date2
    WHEN @Date2 = @Date1 THEN @Date2
    ELSE NULL
  END

END