Question

我有3张桌子： RoomRateChange，RoomRateCotract和DisplayInventory

RoomRateChange：

| RoomID|RateID|Description|RateDate
----------------------
|   101   |  701|   abc       | 2013-04-01 00:00:00.000|

RoomRateCotract：

| RoomID|RateID|           StartDate    |           EndDate      |Description
----------------------------------------------------------------------------------------
|   101   |  701|2013-04-01 00:00:00.000| 2013-04-30 00:00:00.000|null

DisplayInventory：

| RoomID|RateID|Description|RateDate
----------------------

我陷入困境。对于特定的RoomID，RateID和特定日期，如果我在RoomRateChange中有数据，那么我应该在第3个表（DisplayInventory）中添加RoomRateChange的描述值，否则我应该从RoomRateCotract表中选择描述的值。

对于上述情况，输出应为

DisplayInventory

| RoomID|RateID|Description|RateDate
----------------------
|   101   |  701|  abc     | 2013-04-01 00:00:00.000|
|   101   |  701|  NULL     | 2013-04-02 00:00:00.000|
|   101   |  701|  NULL     | 2013-04-03 00:00:00.000|

依此类推至30日。

我正在使用SQL Server 2008

提前致谢。

Answer 1

看起来您可以使用递归CTE来获得结果：

;with data (roomid, rateid, startdate, enddate, description) as
(
  select roomid, rateid, startdate, enddate, description
  from RoomRateCotract
  union all
  select roomid, rateid, dateadd(day, 1, startdate), enddate, description
  from data
  where dateadd(day, 1, startdate) <= enddate
)
-- insert into DisplayInventory
select 
  r.roomid, 
  r.rateid,
  case 
    when r.ratedate = d.startdate 
    then r.description else d.description end description,
  d.startdate RateDate
from data d
left join RoomRateChange r
  on d.roomid = r.roomid
  and d.rateid = r.rateid

请参阅SQL Fiddle with Demo。

递归部分将获得每个房间的开始/结束日期列表和费率：

;with data (roomid, rateid, startdate, enddate, description) as
(
  select roomid, rateid, startdate, enddate, description
  from RoomRateCotract
  union all
  select roomid, rateid, dateadd(day, 1, startdate), enddate, description
  from data
  where dateadd(day, 1, startdate) <= enddate
)
select *
from data

然后使用结果，您将加入RoomRateChange以获得结果。然后可以使用它来填充DisplayInventory表。

通过组合来自两个表的数据来获取第三表中的条件数据

1 个答案: