SQL Select - 对正在进行分组的行和上一行的值求和

Question

我有这个数据的表格。

ID  IMPACT  TICKETID     OWNER    OWNERGROUP
1   1       TICKET1001            GROUP1
2   2       TICKET1001   USER1
3   3       TICKET1001   USER1
4   4       TICKET1001            GROUP1
5   5       TICKET1001   USER2   
6   6       TICKET1001            GROUP1
7   7       TICKET1001   USER1
8   8       TICKET1002            GROUP1
9   9       TICKET1003            GROUP1
10  10      TICKET1003   USER1

我想根据所有工单的 OWNER 列 IMPACT 值进行总结，并且我知道该怎么做。

SELECT OWNER, SUM (IMPACT)
FROM TABLE
WHERE OWNER IS NOT NULL
GROUP BY OWNER

所以这种情况下的结果是：

USER1 22  (2+3+7+10)
USER2 5   (5)

但是，我还需要从前一行中获取值，其中用户不是票证的所有者，但在那一行之后他获得了所有权。 票证总是首先委托给组 (GROUP1)，然后用户获得所有权。 所以这意味着我应该计算来自 ID 1 和 6 和 9 的 USER1 值（因为他是这些行之后的下一个第一个所有者）和来自 ID 4 的 USER2 值（因为 USER2 是第一个下一个所有者票）。

所以我分组的最终结果应该是：

USER1 38  (1+2+3+6+7+9+10)
USER2 9   (4+5)

TICKET1002 根本没有 OWNER 值，所以不应该计算在内！！！

可以这样计算吗？

提前谢谢你

Answer 1

只需使用lag():

select owner,
       (sum(impact) +
        coalesce(sum(case when prev_owner is null then prev_impact end), 0)
       ) as impact
from (select t.*,
             lag(impact) over (order by id) as prev_impact,
             lag(owner) over (order by id) as prev_owner
      from t
     ) t
where owner is not null
group by owner;

Answer 2

以下是您的问题的解决方案：

SELECT Owner, SUM(Impact)
FROM
(
  SELECT 
  @id:=ID, IMPACT, TICKETID,
  CASE WHEN OWNER IS NULL 
          THEN (SELECT OWNER FROM TABLE1 WHERE ID = @id + 1  AND OWNERGROUP IS NULL)
       ELSE
          OWNER
       END AS OWNER,
  OwnerGroup
FROM Table1 AS s
 ) AS t
WHERE OWNER IS NOT NULL
Group BY OWNER; 

输出：

Owner   SUM(Impact)
USER1   38
USER2   9

这是演示的链接：

http://sqlfiddle.com/#!9/5a614b/22