Question

我有一张这样的表：

LocationId | CreatedDate | HeadCount
-----------+-------------+-----------
1          | 2017-6-5    | 12
3          | 2017-6-5    | 458
5          | 2017-6-5    | 125
1          | 2017-8-5    | 12
5          | 2017-8-5    | 458

我需要找到表中存在于特定日期但在另一个日期不存在的所有LocationIds。因此，在上表中，我需要返回

3          | 2017-6-5    | 458

我正在尝试以下方法，但我想我可能需要使用临时表来完成我的任务。

SELECT * 
FROM HeadCounts a
FULL OUTER JOIN HeadCounts b ON a.LocationId = b.LocationId
WHERE a.CreatedDate = '2017-6-5'
  AND b.CreatedDate = '2017-6-5'
  AND a.LocationId IS NULL
   OR b.LocationId IS NULL

非常感谢任何帮助。

Answer 1

您可以使用WHERE NOT EXISTS：

执行此操作

Select  *
From    HeadCounts  H1
Where Not Exists
(
    Select  *
    From    HeadCounts  H2
    Where   H1.LocationId = H2.LocationId
    And     H1.CreatedDate <> H2.CreatedDate
)

Answer 2

由于您只需要这两个特定日期，因此可以执行此类操作。

select LocationID
    , MAX(CreatedDate)
    , MAX(HeadCount)
from YourTable
where CreatedDate  in ('2017-6-5', '2017-8-5')
group by LocationID
having count(*) <= 1

Answer 3

select LocationId, CreatedDate, HeadCount 
from HeadCounts
where LocationId not in(
    select LocationId from HeadCounts
        where locationid in(
            select LocationId from HeadCounts 
            where CreatedDate = '2017-6-5') 
and CreatedDate != '2017-6-5')

如何在sql的同一个表中找到一个日期而不是另一个日期的记录

3 个答案: