Question

我需要获取Room_IDs报告为空的所有Status，然后仅在以后占用。

这是我用作示例的简化表：

 **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        occupied    3/22/2016
   4        vacant       2/2/2015
   4        vacant      3/24/2015

我的结果应如下所示：

 **Room_Id  Status  Inspection_Date**
    1       vacant      5/15/2015
    1       occupied   12/16/2015
    1       vacant      4/17/2016
    3       vacant      8/27/2015
    3       vacant     12/12/2015
    3       occupied    3/22/2016

Answer 1

以下是exists使用correlated subquery：

的一个选项

select * from yourtable t
where exists (
  select 1
  from yourtable c
  where c.room_id = t.room_id 
  group by c.room_id
  having min(case when status = 'vacant' then inspection_date end) <
         max(case when status = 'occupied' then inspection_date end)
  )

SQL Fiddle Demo

Answer 2

试试这个

;WITH cte 
     AS (SELECT *,
                Row_number()OVER(partition BY [room_id] ORDER BY [inspection_date])rn,                 FROM   YOurtable) 
SELECT room_id, 
       status, 
       [inspection_date] 
FROM   cte a 
WHERE  EXISTS (SELECT 1 
               FROM   cte b 
               WHERE  a.room_id = b.room_id 
                      AND b.rn = 1 
                      AND b.status = 'vacant') 
       AND EXISTS(SELECT 1 
                  FROM   cte c 
                  WHERE  a.room_id = c.room_id 
                         AND c.status = 'occupied')

SQL FIDDLE DEMO

Answer 3

的 SQLFiddle Demo

select * From table1 where room_id in( SELECT room_id FROM (SELECT lag(inspection_date,1,NULL) over (partition BY room_id ORDER BY status DESC) AS prev_Inspection_date, t.* FROM (SELECT room_id, CASE WHEN status='vacant' THEN min(inspection_date) ELSE max(inspection_date) END AS inspection_date, status FROM table1 GROUP BY room_id, status ) t ) s WHERE prev_Inspection_date < inspection_date AND prev_Inspection_date IS NOT NULL)

TSQL：通过查询的条件组

3 个答案: