TSQL ：给定分区的顶部记录（条件）

Question

我需要获取TABLE_A 中的所有记录，其中至少 2 最后一个Status 是空的（相对于Inspection_Date）并且Room_ID 在@987654325 中不存在@。

这是我用作示例的简化表：

TABLE_A：

  Room_Id   Status    Inspection_Date
  -------------------------------------
    1        vacant      5/15/2015
    2        occupied    5/21/2015
    2        vacant      1/19/2016
    1        occupied   12/16/2015
    4        vacant      3/25/2016
    3        vacant      8/27/2015
    1        vacant      4/17/2016
    3        vacant     12/12/2015
    3        vacant      3/22/2016
    4        occupied    2/2/2015
    4        vacant      3/24/2015

TABLE_B：

  Room_Id   Status    Inspection_Date
  ------------------------------------
    1        vacant       5/15/2015
    2        occupied     5/21/2015
    2        vacant       1/19/2016
    1        vacant      12/16/2015
    1        vacant       4/17/2016

我的结果应该是这样的：

   Room_Id  Status  Inspection_Date
   ---------------------------------
    3       vacant      8/27/2015
    3       vacant     12/12/2015
    3       vacant      3/22/2016
    4       occupied    2/2/2015
    4       vacant      3/24/2015
    4       vacant      3/25/2016

我已经尝试过这种方式，它适用于示例，但不适用于我的数据..逻辑不完整：

 With cteA As
(
Select *, Row_Number() Over (Partition By Room_ID, Status Order By     Inspection_Date Desc) RowNum From Table_A 
)
Select * From Table_A Where Room_Id In
(
Select Room_Id 
    From cteA
    Where Room_Id Not In (Select Room_Id From Table_B) 
        And Status = 'vacant' And RowNum > 1 
)
    Order By Room_Id, Inspection_Date

这是架构：

CREATE TABLE TABLE_A (`Room_Id` int, 
                      `Status` varchar(55), 
                      `Inspection_Date` Date
                     );

INSERT INTO TABLE_A (Room_Id, Status, Inspection_Date)
VALUES  (1, 'vacant',      '5/15/2015'),
        (2, 'occupied',    '5/21/2015'),
        (2, 'vacant',      '1/19/2016'),
        (1, 'occupied',   '12/16/2015'),
        (4, 'vacant',      '3/25/2016'),
        (3, 'vacant',      '8/27/2015'),
        (1, 'vacant',      '4/17/2016'),
        (3, 'vacant',     '12/12/2015'),
        (3, 'vacant',      '3/22/2016'),
        (4, 'occupied',       '2/2/2015'),
        (4, 'vacant',      '3/24/2015');

CREATE TABLE TABLE_B (`Room_Id` int, 
                      `Status` varchar(55),         
                      `Inspection_Date` Date
                     );

INSERT INTO TABLE_B (Room_Id, Status, Inspection_Date)
VALUES
        (1, 'vacant',      '5/15/2015'),
        (2, 'occupied',    '5/21/2015'),
        (2, 'vacant',      '1/19/2016'),
        (1, 'vacant',      '12/16/2015'),
        (1, 'vacant',      '4/17/2016'),;

Answer 1

普通

1. 为 TABLE_A 中的每个房间选择最后日期（作为 lastDate）

2. 为 TABLE_A 中的每个房间选择上一个日期（作为 prevLastDate）

3. 从 lastDate 获取状态为“vacant”的 room_ids（如 lastDateVacant）

4. 从状态为“空置”的 prevLastDate 获取 room_ids（如 prevLastDateVacant）

5. 过滤 TABLE_A 以仅包含 lastDateVacant 和 prevLastDateVacant（内部）中的 ID

6. 过滤 TABLE_A 以仅包含不在 TABLE_B 中的 ID（左外 + IS NULL）

结果你有：

WITH lastDate AS (
    SELECT room_id AS room,MAX(inspection_date) AS date
    FROM "TABLE_A"
    GROUP BY room_id
), prevLastDate AS (
    SELECT room_id AS room,MAX(inspection_date) AS date
    FROM "TABLE_A" a
    INNER JOIN lastDate ON a.room_id = lastDate.room and a.inspection_date < lastDate.date
    GROUP BY room_id
), lastDateVacant AS (
    SELECT room_id AS room FROM "TABLE_A"
    WHERE (room_id,inspection_date) IN (
        SELECT room, date FROM lastDate
    ) AND status = 'vacant' 
), prevLastDateVacant AS (
    SELECT room_id AS room FROM "TABLE_A"
    WHERE (room_id,inspection_date) IN (
        SELECT room, date FROM prevLastDate
    ) AND status = 'vacant' 
)

SELECT a.* FROM "TABLE_A" a 
INNER JOIN lastDateVacant 
    ON a.room_id = lastDateVacant.room
INNER JOIN prevLastDateVacant 
    ON a.room_id = prevLastDateVacant.room
LEFT OUTER JOIN "TABLE_B" AS b 
    ON a.room_id = b.room_id    
WHERE b.room_id IS NULL 
ORDER BY a.room_id ASC, a.inspection_date DESC

窗口函数

不确定 TSQL 的语法是否相同，但这里是较短的变体：

1. 按房间分区和/或按日期排序

2. 检查排名为 1 和 2 的 ID 是否处于“空缺”状态，按 ID 分组并多次出现

房间为 ( 从 ( 选择 room_id 作为房间，状态，inspection_date 作为日期， RANK() OVER (PARTITION BY room_id ORDER BY Inspection_date DESC) AS RANK 来自“TABLE_A” ) 其中（排名在（1,2）和状态='空缺'） 按房间分组 计数() > 1 ) 从“TABLE_A”中选择一个。 INNER JOIN 房间 ON a.room_id = room.room 左外连接“TABLE_B”作为 b ON a.room_id = b.room_id
其中 b.room_id 为空 ORDER BY a.room_id ASC, a.inspection_date DESC

Answer 2

您的条件几乎直接转化为查询。您可以将窗口函数用于空计数，将not exists 用于与table_b 的关系：

select a.*
from (select a.*,
             sum(case when status = 'vacant' then 1 else 0 end) over (partition by room_id) as num_vacant
      from table_a a
      where not exists (select 1
                        from table_b b
                        where b.room_id = a.room_id
                       )
    ) a
where num_vacant >= 2;

编辑：

如果您希望最后两个是空的，您可以找到最后一个非空的记录，然后计算比这更大的记录：

select a.*
from (select a.*,
             sum(case when a2.max_nonvacant > a.inspection_date then 0 else 1) over (partition by room_id) as num_vacant_last
      from table_a a outer apply
           (select max(inspection_date) as max_nonvacant
            from table_a a2
            where a2.room_id = a.room_id and a2.status <> 'vacant'
           ) a2
      where not exists (select 1
                        from table_b b
                        where b.room_id = a.room_id
                       )
    ) a
where num_vacant_last >= 2;

Answer 3

这对我有用，我已经检查了一遍又一遍。

with Rooms as (
select
    Room_Id, Status,
    row_number() over (partition by Room_Id order by Inspection_Date desc) as rn
from TABLE_A
), Candidates as (
select Room_Id from Rooms group by Room_Id
having sum(case when rn in (1, 2) and Status = 'vacant' then 1 else null end) = 2
)
select * from TABLE_A
where Room_Id in (select Room_Id from Candidates except select Room_Id from TABLE_B)
order by Room_Id, Inspection_Date desc

Answer 4

我做了这个测试： 提取考虑到与inspection_date（降序）相关的最后两个Status（相等状态）的所有room_id：

select * from TABLE_A WHERE [Room_Id] IN
(
    SELECT [Room_Id] FROM 
    (SELECT ROW_NUMBER() OVER(PARTITION BY [Room_Id] ORDER BY [Inspection_Date] DESC ) AS id,   
      [Room_Id],[Status],[Inspection_Date]
      FROM TABLE_A 
      ) AA
    WHERE AA.ID <=2
--selecting the last two Inspection_Date
 and [Status] = 'vacant'  
            GROUP BY [Room_Id],[Status] HAVING COUNT(*) >1          
) 
AND 
[Room_Id] NOT IN (SELECT Room_Id FROM TABLE_B)
order by Room_Id, Inspection_Date desc