SQLite每天计算的产品交易总金额

Question

我有一个表（储藏室）用作分类帐，仅当发生交易时，才会随着时间记录产品的添加和移除。我想每天获取所有产品的运行总和。可能会有更好的方法来获得此结果，但我不想透视表。

我想要得到的结果是这里表中的结果。非常感谢！

Answer 1

您可以CROSS将递归CTE连接到表的不同乘积，然后将LEFT连接到表以使用SUM()窗口函数获得运行总和：

with dates as (
  select min(date) date from pantry
  union all
  select date(date, '+1 day')
  from dates
  where date < (select max(date) from pantry)
)
select *
from (
  select d.date, p.produce,
        sum(t.transactions) over (partition by p.produce order by d.date) running_sum
  from dates d 
  cross join (select distinct produce from pantry) p
  left join pantry t on t.date = d.date and t.produce = p.produce
)
where running_sum is not null
order by date

请参见demo。
结果：

> date       | produce | running_sum
> :--------- | :------ | ----------:
> 2020-01-01 | banana  |          50
> 2020-01-02 | banana  |          50
> 2020-01-03 | apple   |           5
> 2020-01-03 | banana  |          40
> 2020-01-04 | apple   |           5
> 2020-01-04 | banana  |          40
> 2020-01-05 | apple   |           5
> 2020-01-05 | banana  |          40
> 2020-01-06 | apple   |           5
> 2020-01-06 | banana  |          40
> 2020-01-07 | apple   |           3
> 2020-01-07 | banana  |          20
> 2020-01-07 | grapes  |         100
> 2020-01-08 | apple   |           3
> 2020-01-08 | banana  |          20
> 2020-01-08 | grapes  |         100
> 2020-01-09 | apple   |           3
> 2020-01-09 | banana  |          20
> 2020-01-09 | grapes  |          50
> 2020-01-10 | apple   |           3
> 2020-01-10 | banana  |          20
> 2020-01-10 | grapes  |          50
> 2020-01-11 | apple   |          -1
> 2020-01-11 | banana  |          20
> 2020-01-11 | grapes  |          50
> 2020-01-11 | melon   |           2