从总体积计算每日体积

Question

我有以下数据：

ID	Date	Total
A	2021-09-03	0
A	2021-09-04	12
A	2021-09-05	37
A	2021-09-06	40
B	2021-08-03	20
B	2021-08-04	43
B	2021-08-05	75

根据这些数据，我想得到以下 table：

ID	Date	Total	Daily
A	2021-09-03	0	0
A	2021-09-04	12	12
A	2021-09-05	37	25
A	2021-09-06	40	3
B	2021-08-03	20	20
B	2021-08-04	43	23
B	2021-08-05	75	32

我尝试了下面的代码，但是我得到了很多重复的代码：

CREATE TABLE table_b AS (
SELECT a.ID, a.Date, a.Total,
a.Total - coalesce(b.Total, 0) AS Daily
FROM table_a a left outer JOIN table_a b
ON (a.ID = b.ID AND b.Date < a.Date));

提前致谢:)

Answer 1

SELECT *,
       Total - COALESCE(LAG(Total) OVER (PARTITION BY id ORDER BY `date`), 0) Daily
FROM src_table

从总体积计算每日体积

Calculating daily volumes from total volume

mysql

sql

heidisql