从下一行到当前行中选择一个值

Question

我一直试图在SQL Server中编写查询，这将帮助我获得用户的下一个操作时间作为上一条记录的操作结束。我如何查询以获取下一个操作的结束日期，而查询的最后一条记录将没有其他记录，那么我正在尝试获取sysdate

SELECT
  UL.UL_US_ID,
  UL_ACTION_TIME
FROM USER_LOG UL
JOIN USER_MAIN UM
  ON UL.UL_US_ID = UM.US_ID
WHERE UL.UL_ACTION IN ('LI')
AND UM.US_UT_ID = '1'
AND CONVERT(varchar(10), UL.UL_ACTION_TIME, 111) = CONVERT(varchar(10), GETDATE(), 111)
ORDER BY ul.UL_US_ID, ul.UL_ACTION_TIME;

***Existing Data Sample***
+----------+-----------------+
|   user   |   acton_time    |
+----------+-----------------+
| hudhaifa | 8/27/2019 9:03  |
| hudhaifa | 8/27/2019 9:40  |
| hudhaifa | 8/27/2019 9:51  |
| hudhaifa | 8/27/2019 10:41 |
| hudhaifa | 8/27/2019 10:56 |
+----------+-----------------+

***Required Data Sample***
+----------+-----------------+-----------------+
|   user   |   acton_time    |   action_end    |
+----------+-----------------+-----------------+
| hudhaifa | 8/27/2019 9:03  | 8/27/2019 9:40  |
| hudhaifa | 8/27/2019 9:40  | 8/27/2019 9:51  |
| hudhaifa | 8/27/2019 9:51  | 8/27/2019 10:41 |
| hudhaifa | 8/27/2019 10:41 | 8/27/2019 10:56 |
| hudhaifa | 8/27/2019 10:56 | sysdate         |
+----------+-----------------+-----------------+

Answer 1

假定SQL Server（或任何支持解析功能的RDBMS）仅使用LEAD函数：

SELECT user
     , action_time
     , LEAD(action_time, 1, CURRENT_TIMESTAMP) OVER (PARTITION BY user ORDER BY action_time ASC) AS action_end
FROM t