SQL 查询具有最后结束日期的非活动用户

Question

这是我在一年前提出的一个问题的后续旧线程当时我得到的答案运行良好，但现在我发现我需要调整查询才能获得非活动用户的最新结束日期。

所以这里有一个用户的快速示例表，有些是活跃的，有些是不活跃的，有些有几个工作时期。

当某人重新就业时，将为该就业期间添加一个新行。 用户名将始终相同。

因此，如果有多个工作期，我想找出哪些用户被禁用并且没有积极的工作，我想要一个具有最晚结束日期的用户。 每个用户名一行，包含所有列。

该数据库是 SQL Server 2016。

示例表：

|  username | name       | active | Job title   | enddate 
+-----------+----------- +--------+-------------+----------
| 1111      | Jane Doe   |    1   | CIO         | 1/3/2022
| 1111      | Jane Doe   |    0   | Janitor     | 1/2/2018
| 1112      | Bob Doe    |    1   | Coder       | NULL
| 1113      | James Doe  |    0   | Coder       | 1/3/2018
| 1114      | Ray Doe    |    1   | Manager     | NULL
| 1114      | Ray Doe    |    0   | Clerk       | 2/2/2019
| 1115      | Emma Doe   |    1   | Waiter      | NULL
| 1116      | Sarah Doe  |    0   | Greeter     | 3/4/2016
| 1116      | Sarah Doe  |    0   | Trainer     | 4/5/2019

因此，对于用户 1116，我理想情况下会得到一行 enddate 4/5/2019

我从旧线程的答案中使用的查询是这个：

    ;WITH NonActiveDisabledUsers AS
(
    SELECT DISTINCT
        U.username
    FROM
        UserEmployment AS U
    WHERE
        U.active = 0 AND
        NOT EXISTS (SELECT 'no current active employment' 
                    FROM UserEmployment AS C
                    WHERE U.username = C.username AND 
                    C.active = 1 AND
                    (C.enddate IS NULL OR C.enddate >= CONVERT(DATE, GETDATE())))
)
SELECT
    R.*
FROM
    NonActiveDisabledUsers AS N
    CROSS APPLY (
        SELECT TOP 1        -- Just 1 record
            U.*
        FROM
            UserEmployment AS U
        WHERE
            N.username = U.username AND
            U.active = 0
        ORDER BY
            U.enddate DESC  -- Determine which record should we display
        ) AS R

这为我提供了正确的用户和就业状态，但不是最新的结束日期，因为它将为用户 1116 获得第一个结果

Answer 1

我们可以使用带有 window 聚合的条件聚合来获取该用户的活动行数。

然后我们过滤到仅非活动状态，并通过enddate对结果进行行编号，每组取第一行：

SELECT
    username,
    name,
    active,
    [Job title],
    enddate 
FROM (
    SELECT *, rn = ROW_NUMBER() OVER (PARTITION BY username ORDER BY enddate DESC)
    FROM (
        SELECT *,
          CountOfActive = COUNT(CASE WHEN
                Active = 1 AND
                (enddate IS NULL OR enddate >= CONVERT(DATE, GETDATE())) THEN 1 END
              ) OVER (PARTITION BY username)
        FROM UserEmployment
    ) AS t
    WHERE CountOfActive = 0
) AS t
WHERE rn = 1;

请注意，行编号不考虑最后排序的enddate中的空值。 你需要一个条件排序：

ROW_NUMBER() OVER (PARTITION BY username ORDER BY CASE WHEN enddate IS NULL THEN 0 ELSE 1 END ASC, enddate DESC)

Answer 2

嗯。 . . 我认为您可以获取最新记录并检查它是否处于非活动状态：

select ue.*
from (select ue.*,
             row_number() over (partition by user_id
                                order by active desc, enddate desc
                               ) as seqnum
      from UserEmployment ue
     ) ue
where seqnum = 1 and active = 0;

Answer 3

这是一个将产生所需结果的变体：

 SELECT distinct username, max(enddate)  
  FROM UserEmployment as t1
  WHERE
    t1.active = 0 AND 
    NOT EXISTS (select username from UserEmployment as t2 WHERE active = 1 AND
                    (t2.enddate IS NULL OR t2.enddate >= CONVERT(DATE, GETDATE())) AND
                     t1.username = t2.username)
  GROUP BY username