我试图在 MSSQL 中为这个示例表获取按活动 ID、日期 ID 和个人 ID 分组的最小开始和最大停止。
源表如下所示：
+--------+--------+------------------+------------------+------------+ | USERID | DATEID | START | END | ACTIVITYID | +--------+--------+------------------+------------------+------------+ | 1 | 1 | 11/01/2021 12:10 | 11/01/2021 12:15 | A | | 1 | 1 | 11/01/2021 12:15 | 11/01/2021 12:30 | A | | 1 | 1 | 11/01/2021 12:30 | 11/01/2021 12:45 | A | | 1 | 1 | 11/01/2021 12:45 | 11/01/2021 13:00 | A | | 1 | 1 | 11/01/2021 13:00 | 11/01/2021 13:15 | A | | 1 | 1 | 11/01/2021 13:15 | 11/01/2021 13:30 | A | | 1 | 1 | 11/01/2021 13:30 | 11/01/2021 13:45 | A | | 1 | 1 | 11/01/2021 13:45 | 11/01/2021 13:55 | A | | 1 | 1 | 11/01/2021 13:55 | 11/01/2021 14:00 | B | | 1 | 1 | 11/01/2021 14:00 | 11/01/2021 14:05 | B | | 1 | 1 | 11/01/2021 14:05 | 11/01/2021 14:15 | A | | 1 | 1 | 11/01/2021 14:15 | 11/01/2021 14:30 | A | | 1 | 1 | 11/01/2021 14:30 | 11/01/2021 14:45 | A | | 1 | 1 | 11/01/2021 14:45 | 11/01/2021 15:00 | A | | 1 | 1 | 11/01/2021 15:00 | 11/01/2021 15:10 | A | | 1 | 1 | 11/01/2021 15:10 | 11/01/2021 15:15 | C | | 1 | 1 | 11/01/2021 15:15 | 11/01/2021 15:30 | C | | 1 | 1 | 11/01/2021 15:30 | 11/01/2021 15:45 | C | | 1 | 1 | 11/01/2021 15:45 | 11/01/2021 16:00 | C | | 1 | 1 | 11/01/2021 16:00 | 11/01/2021 16:10 | C | | 1 | 1 | 11/01/2021 16:10 | 11/01/2021 16:15 | A | | 1 | 1 | 11/01/2021 16:15 | 11/01/2021 16:30 | A | | 1 | 1 | 11/01/2021 16:30 | 11/01/2021 16:45 | A | | 1 | 1 | 11/01/2021 16:45 | 11/01/2021 17:00 | A | | 1 | 1 | 11/01/2021 17:00 | 11/01/2021 17:15 | A | | 1 | 1 | 11/01/2021 17:15 | 11/01/2021 17:30 | A | | 1 | 1 | 11/01/2021 17:30 | 11/01/2021 17:45 | A | | 1 | 1 | 11/01/2021 17:45 | 11/01/2021 18:00 | A | | 1 | 1 | 11/01/2021 18:00 | 11/01/2021 18:15 | A | | 1 | 1 | 11/01/2021 18:15 | 11/01/2021 18:30 | A | | 1 | 1 | 11/01/2021 18:30 | 11/01/2021 18:40 | A | | 1 | 1 | 11/01/2021 18:40 | 11/01/2021 18:45 | B | | 1 | 1 | 11/01/2021 18:45 | 11/01/2021 18:50 | B | | 1 | 1 | 11/01/2021 18:50 | 11/01/2021 19:00 | A | | 1 | 1 | 11/01/2021 19:00 | 11/01/2021 19:15 | A | | 1 | 1 | 11/01/2021 19:15 | 11/01/2021 19:30 | A | | 1 | 1 | 11/01/2021 19:30 | 11/01/2021 19:45 | A | | 1 | 1 | 11/01/2021 19:45 | 11/01/2021 20:00 | A | | 1 | 1 | 11/01/2021 20:00 | 11/01/2021 20:15 | A | | 1 | 1 | 11/01/2021 20:15 | 11/01/2021 20:30 | A | | 1 | 1 | 11/01/2021 20:30 | 11/01/2021 20:45 | A | | 1 | 1 | 11/01/2021 20:45 | 11/01/2021 21:00 | A | +--------+--------+------------------+------------------+------------+
最终结果应该是这样的：
+--------+--------+------------------+------------------+------------+ | USERID | DATEID | START | END | ACTIVITYID | +--------+--------+------------------+------------------+------------+ | 1 | 1 | 11/01/2021 12:10 | 11/01/2021 13:55 | A | | 1 | 1 | 11/01/2021 13:55 | 11/01/2021 14:05 | B | | 1 | 1 | 11/01/2021 14:05 | 11/01/2021 15:10 | A | | 1 | 1 | 11/01/2021 15:10 | 11/01/2021 16:10 | C | | 1 | 1 | 11/01/2021 16:10 | 11/01/2021 18:40 | A | | 1 | 1 | 11/01/2021 18:40 | 11/01/2021 18:50 | B | | 1 | 1 | 11/01/2021 18:50 | 11/01/2021 21:00 | A | +--------+--------+------------------+------------------+------------+
我尝试使用上一行/下一行值，但它只会返回上一行，但无法获取第一行和最后一行。
感谢您的帮助！
答案 0 :(得分：1)
这是一种间隙和孤岛问题。假设相邻的值没有间隙，那么行号的差异是最简单的方法：
select userid, dateid, activityid,
min(start), max(end)
from (select t.*,
row_number() over (partition by userid, dateid order by start) as seqnum,
row_number() over (partition by userid, dateid, activity_id order by start) as seqnum_2
from t
) t
group by userid, dateid, activityid, (seqnum - seqnum_2)
order by userid, dateid, min(start);
请注意，start 和 end 是非常糟糕的列名选择，因为它们是 SQL 关键字。我想你的真名更安全。