不同产品在不同日期的复杂增量累积总和

Question

我试图弄清楚如何在每个日期计算每个产品，以便计数在所有产品中都是递增的，

这是用于理解的虚拟表，我有数百万条记录，包含数千种不同的产品

我无法在每个日期查询每种产品的增量计数以及提供的日期的里程数

[![在此处输入图片描述][1]][1]

CREATE TABLE Dummy_tab (
    empid int,
    date1_start date,
    name_emp varchar(255),
    product varchar(255),
    miles varchar(20)
);
 

INSERT INTO Dummy_tab VALUES
  (1, '2018-08-27', 'Eric', 'a',10),
  (1, '2018-08-28', 'Eric','b',10),
  (1, '2018-08-28', 'Eric','a',20),
  (2, '2020-01-8', 'Jack','d',10),
  (2, '2020-02-8', 'Jack','b',20),
  (2, '2020-12-28', 'Jack','b',20),
  (2, '2020-12-28', 'Jack','d',20),
  (2,'2021-10-28', 'Jack','c',20),
  (2, '2022-12-28', 'Jack','d',20),
  (3, '2018-12-31', 'Jane','',10),
  (3, '2018-12-31', 'Jane','',15);


```

My desired O/p is this 

Id  Date        a   b   c   d empty miles
1   2018-08-27  1   0   0   0   0   10
1   2018-08-28  2   1   0   0   0   20
2   2020-01-08  0   0   0   1   0   10
2   2020-02-08  0   1   0   1   0   20
2   2020-12-28  0   2   0   2   0   20
2   2021-10-28  0   2   1   2   0   20
2   2022-12-28  0   2   1   3   0   20
3   2018-12-31  0   0   0   0   1   10
3   2019-12-31  0   0   0   0   2   15


FOR EXAMPLE

Eric has 3 entry for ID =1 with product a on 2018 08 27 with product b on 2018 08 28 with product a on 2018 08 28

SO 1st entry a= 1 for ID=1 2nt entry is sum of previous and current so now a =2 for ID=1 and b= 1 as there were no entry earlier for b

Miles needs to be maximum miles for that date from past dates