T-SQL 当前和以前的状态

Question

我有一个数据库，我想从中获取当前房间号和以前的房间号。

数据是这样的。 TableX

Name, room_number, Start_Date, End_Date, status
Bob, A1, 2015-04-03, null, transfer
Bob, B5, 2013-04-15, 2015-04-03, somestatus
Bob, B7, 2011-04-15, 2013-04-15, someotherstatus
Smith, A2, 2015-04-03, null, transfer
Smith, B4, 2013-10-15, 2015-04-03, someotherstatus
Smith, B8, 2011-04-15, 2013-10-15, somestatus

我要带回来的是下面的。

Bob, A1, 2015-04-03, null, 调入当前房间 Bob, B5, 2013-04-15, 2015-04-03 上一个房间 Smith, A2, 2015-04-03, null, 转让 Current Room Smith, B4, 2013-10-15, 2015-04-03 上一个房间

如果这足够清楚，请告诉我。

我目前拥有的是

Select Name, room_number, Start_Date, End_Date, status
from TableX
where start_date = today
and status = transfer

这给了我所有的人房间。不确定如何获得以前的房间号，因为转移之外的状态没有任何意义。共同点是，如果是他们当前的房间，结束日期不为空

谢谢

Answer 1

CREATE VIEW RoomChange
AS
WITH CTE
AS
(

    SELECT  Name,
            room_number,
            [Start_Date],
            [end_date],
            ROW_NUMBER() OVER (PARTITION BY name ORDER BY [Start_date]) room_order
    FROM TableX
)


SELECT  A.name,
        A.[Start_Date],
        A.room_number,
        B.[Start_Date] prev_room_start,
        B.room_number AS prev_room
FROM CTE A
INNER JOIN CTE B
ON  A.room_order = B.room_order + 1
    AND A.Name = B.name
WHERE A.[end_date] IS NULL --only grab latest room
GO


SELECT *
FROM RoomChange

结果：

name  Start_Date room_number prev_room_start prev_room
----- ---------- ----------- --------------- ---------
Bob   2015-04-03 A1          2013-04-15      B5
Smith 2015-04-03 A2          2013-10-15      B4

T-SQL 当前和以前的状态

T-SQL Current and Previous Status

tsql

sql-server

mssql-jdbc