计算下条记录与上条记录日期天数之差

USE [test]
GO
/****** Object:  Table [dbo].[liu_shui]    Script Date: 11/13/2015 09:34:50 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[liu_shui](
    [d_date] [date] NOT NULL,
    [i_id] [int] IDENTITY(1,1) NOT NULL,
 CONSTRAINT [PK_liu_shui] PRIMARY KEY CLUSTERED 
(
    [i_id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET IDENTITY_INSERT [dbo].[liu_shui] ON
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xA73A0B00 AS Date), 1)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xA83A0B00 AS Date), 2)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xA93A0B00 AS Date), 3)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xAA3A0B00 AS Date), 4)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xAB3A0B00 AS Date), 5)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xAD3A0B00 AS Date), 6)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xAF3A0B00 AS Date), 8)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xB03A0B00 AS Date), 9)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xB23A0B00 AS Date), 11)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xB33A0B00 AS Date), 12)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xB53A0B00 AS Date), 13)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xB83A0B00 AS Date), 14)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xB93A0B00 AS Date), 15)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xBA3A0B00 AS Date), 16)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xBB3A0B00 AS Date), 17)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xBC3A0B00 AS Date), 18)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xBD3A0B00 AS Date), 19)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xBE3A0B00 AS Date), 20)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xBF3A0B00 AS Date), 21)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC03A0B00 AS Date), 22)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC13A0B00 AS Date), 23)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC23A0B00 AS Date), 24)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC33A0B00 AS Date), 25)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC43A0B00 AS Date), 26)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC53A0B00 AS Date), 27)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC63A0B00 AS Date), 28)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC73A0B00 AS Date), 29)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC83A0B00 AS Date), 30)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xC93A0B00 AS Date), 31)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xCB3A0B00 AS Date), 32)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xCC3A0B00 AS Date), 33)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xCD3A0B00 AS Date), 34)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xCE3A0B00 AS Date), 35)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xCF3A0B00 AS Date), 36)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD03A0B00 AS Date), 37)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD13A0B00 AS Date), 38)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD33A0B00 AS Date), 39)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD63A0B00 AS Date), 40)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD73A0B00 AS Date), 41)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD83A0B00 AS Date), 42)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xD93A0B00 AS Date), 43)
INSERT [dbo].[liu_shui] ([d_date], [i_id]) VALUES (CAST(0xDA3A0B00 AS Date), 44)
SET IDENTITY_INSERT [dbo].[liu_shui] OFF
go



/******计算日期差，方法1  ******/


SELECT 
       a.[i_id]
      ,a.[d_date]
      ,日期差=
       COALESCE(DATEDIFF(DAY,b.d_date,a.d_date),0)
  FROM [test].[dbo].[liu_shui] as a
  outer apply
  (select b.d_date from test.dbo.liu_shui b
    where a.i_id-b.i_id=1) as b
 go
 /*计算日期差，方法2*/
 SELECT 
       a.[i_id]
      ,a.[d_date]
      ,日期差=
       coalesce(
                 (
                 select DATEDIFF(DAY,b.d_date,a.d_date) from test.dbo.liu_shui b
                 where a.i_id-b.i_id =1
                 ),0
                )
  FROM [test].[dbo].[liu_shui] as a