利用sql标量值函数取得指定日期当前季度首月份/结束月份

-- =============================================
-- Author:  <lk>
-- Create date: <2008-9-19>
-- Description: <用于季度统计>/*返回季度开始月 */
--调用方法：select dbo.sys_GetQuarterBeginDate('2008-11-1')
-- =============================================

ALTER FUNCTION [dbo].[sys_GetQuarterBeginDate](@month smalldatetime)
RETURNS smalldatetime

AS

--function : 返回季度的开始月
BEGIN

DECLARE @dt smalldatetime

IF MONTH(@month) < 4
      SET @dt = CONVERT(VARCHAR,YEAR(@month) )+ '-1-1'
ELSE
BEGIN
      IF MONTH(@month) < 7
         SET @dt = CONVERT(VARCHAR,YEAR(@month))+ '-4-1'
      ELSE
        BEGIN
IF MONTH(@month) < 10
     SET @dt = CONVERT(VARCHAR,YEAR(@month)) + '-7-1'
ELSE
     SET @dt = CONVERT(VARCHAR,YEAR(@month) )+ '-10-1'
        END
END

    RETURN @dt

END

-- =============================================
-- Author:  <lk>
-- Create date: <2008-9-19>
-- Description: *返回季度结束月 */
--调用：select dbo.sys_GetQuarterEndDate('2008-11-1')
-- =============================================

ALTER FUNCTION [dbo].[sys_GetQuarterEndDate](@month smalldatetime)
RETURNS smalldatetime

AS

--function : 返回季度的结束月
BEGIN

DECLARE @dt smalldatetime

IF MONTH(@month) < 4
      SET @dt = CONVERT(VARCHAR,YEAR(@month) )+ '-3-31'
ELSE
BEGIN
      IF MONTH(@month) < 7
         SET @dt = CONVERT(VARCHAR,YEAR(@month))+ '-6-30'
      ELSE
        BEGIN
IF MONTH(@month) < 10
     SET @dt = CONVERT(VARCHAR,YEAR(@month)) + '-9-30'
ELSE
     SET @dt = CONVERT(VARCHAR,YEAR(@month) )+ '-12-31'
        END
END

    RETURN @dt

END