用于计算前一行的行总和的SQL查询

Question

这是我的表

date     count of subscription per date
----      ----------------------------
21-03-2016      10
22-03-2016      30
23-03-2016      40 

请你需要帮助，我需要得到如下表所示的结果，第一行的第二行求和，另一行的相同内容：

date     count of subscription per date
----      ----------------------------
21-03-2016      10
22-03-2016      40
23-03-2016      80 

Answer 1

Select sum(col1) over(order by date rows between unbounded preceding and current row) cnt from mytable;

Answer 2

您可以使用ANSI标准分析SUM()函数执行累积求和：

select date, sum(numsubs) over (order by date) as cume_numsubs
from t;

Answer 3

SELECT t.date, (
    SELECT SUM(numsubs) 
    FROM mytable t2 
    WHERE t2.date <= t.date
) AS cnt
FROM mytable t