sql - 累积汇总列

Question

我可能需要一些关于 SQL 语句的帮助。所以我有一个看起来像这样的表格“cont”：

cont_id     name       weight
----------- ---------- -----------
1           1          10
2           1          20
3           2          40
4           2          15
5           2          20
6           3          15
7           3          40
8           4          60
9           5          10
10          6          5

然后我总结了权重列并按名称对其进行分组：

name       wsum
---------- -----------
2          75
4          60
3          55
1          30
5          10
6          5

结果应该有一个累积列，应该如下所示：

name       wsum        acc_wsum
---------- ----------- ------------
2          75          75
4          60          135
3          55          190
1          30          220
5          10          230
6          5           235

但我没有设法让最后一条语句起作用..

编辑：这个声明做到了（感谢戈登）

select t.*,
    (select sum(wsum) from (select name, SUM(weight) wsum
    from cont
    group by name)
    t2 where t2.wsum > t.wsum or (t2.wsum = t.wsum and t2.name <= t.name)) as acc_wsum
from (select name, SUM(weight) wsum
from cont
group by name) t
order by wsum desc

Answer 1

因此，最好的方法是使用累积和：

select t.*,
       sum(wsum) over (order by wsum desc) as acc_wsum
from (<your summarized query>) t

该order by条款使这种累积。

如果您没有该功能（在 SQL Server 2012 和 Oracle 中），则关联子查询是一种简单的方法，假设总权重是不同的值：

select t.*,
       (select sum(wsum) from (<your summarized query>) t2 where t2.wsum >= t.wsum) as acc_wsum
from (<your summarized query>) t

这应该适用于所有 SQL 方言。要处理累积权重可能重复的情况：

select t.*,
       (select sum(wsum) from (<your summarized query>) t2 where t2.wsum > t.wsum or (t2.wsum = t.wsum and t2.name <= t.name) as acc_wsum
from (<your summarized query>) t

Answer 2

尝试这个

;WITH CTE
AS
(
 SELECT *,
ROW_NUMBER() OVER(ORDER BY wsum) rownum
FROM @table1
 ) 
 SELECT 
 c1.name, 
 c1.wsum,
 acc_wsum= (SELECT SUM(c2.wsum) 
                   FROM cte c2
                   WHERE c2.rownum <= c1.rownum)
 FROM CTE c1;

或者您可以加入而不是使用子查询

;WITH CTE
AS
(
 SELECT *,
ROW_NUMBER() OVER(ORDER BY usercount) rownum
 FROM @table1
) 
 SELECT 
 c1.name, 
 c1.wsum,
 acc_wsum= SUM(c2.wsum) 
 FROM CTE c1
 INNER JOIN CTE c2 ON c2.rownum <= c1.rownum
 GROUP BY c1.name, c1.wsum;