MySQL 8.0

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CREATE TABLE contracts_balance(
  id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
    contract_id_fk int(11) not null,
  contract_prod VARCHAR(30) NOT NULL,
    product_name VARCHAR(30) NOT NULL,
      pack_size VARCHAR(30) NOT NULL,
            member VARCHAR(30) NOT NULL,
               balance_aftermonth int(11) NOT NULL,
                   monthlydates DATE NOT NULL,

  start_date DATE,
  end_Date DATE);
INSERT INTO contracts_balance (contract_id_fk,contract_prod,product_name,pack_size,member,monthlydates,balance_aftermonth,start_date, end_date)
VALUES 
('11','Milk','semi skimmed milk','1ltr','member a','2021-07-12','8','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','1ltr','member a','2021-08-12','2','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','1ltr','member a','2021-09-12','3','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','1ltr','member b','2021-07-12','5','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','1ltr','member b','2021-08-12','1','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','1ltr','member b','2021-09-12','1','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','2ltr','member a','2021-07-12','2','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','2ltr','member a','2021-08-12','12','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','2ltr','member a','2021-09-12','4','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','2ltr','member b','2021-07-12','4','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','2ltr','member b','2021-08-12','2','2021-07-12', '2021-09-13'),
('11','Milk','semi skimmed milk','2ltr','member b','2021-09-12','2','2021-07-12', '2021-09-13'),

 ('22','Milk','semi skimmed milk','1ltr','member a','2019-07-12','3','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','1ltr','member a','2019-08-12','6','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','1ltr','member a','2019-09-12','30','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','1ltr','member b','2019-07-12','50','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','1ltr','member b','2019-08-12','10','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','1ltr','member b','2019-09-12','10','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','2ltr','member a','2019-07-12','20','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','2ltr','member a','2019-08-12','12','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','2ltr','member a','2019-09-12','24','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','2ltr','member b','2019-07-12','44','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','2ltr','member b','2019-08-12','2','2019-07-12', '2019-09-13'),
('22','Milk','semi skimmed milk','2ltr','member b','2019-09-12','21','2019-07-12', '2019-09-13')
select *from contracts_balance


id
contract_id_fk
contract_prod
product_name
pack_size
member
balance_aftermonth
monthlydates
start_date
end_Date


1
11
Milk
semi skimmed milk
1ltr
member a
8
2021-07-12
2021-07-12
2021-09-13

2
11
Milk
semi skimmed milk
1ltr
member a
2
2021-08-12
2021-07-12
2021-09-13

3
11
Milk
semi skimmed milk
1ltr
member a
3
2021-09-12
2021-07-12
2021-09-13

4
11
Milk
semi skimmed milk
1ltr
member b
5
2021-07-12
2021-07-12
2021-09-13

5
11
Milk
semi skimmed milk
1ltr
member b
1
2021-08-12
2021-07-12
2021-09-13

6
11
Milk
semi skimmed milk
1ltr
member b
1
2021-09-12
2021-07-12
2021-09-13

7
11
Milk
semi skimmed milk
2ltr
member a
2
2021-07-12
2021-07-12
2021-09-13

8
11
Milk
semi skimmed milk
2ltr
member a
12
2021-08-12
2021-07-12
2021-09-13

9
11
Milk
semi skimmed milk
2ltr
member a
4
2021-09-12
2021-07-12
2021-09-13

10
11
Milk
semi skimmed milk
2ltr
member b
4
2021-07-12
2021-07-12
2021-09-13

11
11
Milk
semi skimmed milk
2ltr
member b
2
2021-08-12
2021-07-12
2021-09-13

12
11
Milk
semi skimmed milk
2ltr
member b
2
2021-09-12
2021-07-12
2021-09-13

13
22
Milk
semi skimmed milk
1ltr
member a
3
2019-07-12
2019-07-12
2019-09-13

14
22
Milk
semi skimmed milk
1ltr
member a
6
2019-08-12
2019-07-12
2019-09-13

15
22
Milk
semi skimmed milk
1ltr
member a
30
2019-09-12
2019-07-12
2019-09-13

16
22
Milk
semi skimmed milk
1ltr
member b
50
2019-07-12
2019-07-12
2019-09-13

17
22
Milk
semi skimmed milk
1ltr
member b
10
2019-08-12
2019-07-12
2019-09-13

18
22
Milk
semi skimmed milk
1ltr
member b
10
2019-09-12
2019-07-12
2019-09-13

19
22
Milk
semi skimmed milk
2ltr
member a
20
2019-07-12
2019-07-12
2019-09-13

20
22
Milk
semi skimmed milk
2ltr
member a
12
2019-08-12
2019-07-12
2019-09-13

21
22
Milk
semi skimmed milk
2ltr
member a
24
2019-09-12
2019-07-12
2019-09-13

22
22
Milk
semi skimmed milk
2ltr
member b
44
2019-07-12
2019-07-12
2019-09-13

23
22
Milk
semi skimmed milk
2ltr
member b
2
2019-08-12
2019-07-12
2019-09-13

24
22
Milk
semi skimmed milk
2ltr
member b
21
2019-09-12
2019-07-12
2019-09-13


select contract_prod , start_date , end_date, sum(balance_aftermonth) 
from contracts_balance 
where MONTH(monthlydates) = MONTH(curdate())

group by contract_prod, start_date,end_date 


contract_prod
start_date
end_date
sum(balance_aftermonth)


Milk
2021-07-12
2021-09-13
17

Milk
2019-07-12
2019-09-13
30

id	contract_id_fk	contract_prod	product_name	pack_size	member	balance_aftermonth	monthlydates	start_date	end_Date
1	11	Milk	semi skimmed milk	1ltr	member a	8	2021-07-12	2021-07-12	2021-09-13
2	11	Milk	semi skimmed milk	1ltr	member a	2	2021-08-12	2021-07-12	2021-09-13
3	11	Milk	semi skimmed milk	1ltr	member a	3	2021-09-12	2021-07-12	2021-09-13
4	11	Milk	semi skimmed milk	1ltr	member b	5	2021-07-12	2021-07-12	2021-09-13
5	11	Milk	semi skimmed milk	1ltr	member b	1	2021-08-12	2021-07-12	2021-09-13
6	11	Milk	semi skimmed milk	1ltr	member b	1	2021-09-12	2021-07-12	2021-09-13
7	11	Milk	semi skimmed milk	2ltr	member a	2	2021-07-12	2021-07-12	2021-09-13
8	11	Milk	semi skimmed milk	2ltr	member a	12	2021-08-12	2021-07-12	2021-09-13
9	11	Milk	semi skimmed milk	2ltr	member a	4	2021-09-12	2021-07-12	2021-09-13
10	11	Milk	semi skimmed milk	2ltr	member b	4	2021-07-12	2021-07-12	2021-09-13
11	11	Milk	semi skimmed milk	2ltr	member b	2	2021-08-12	2021-07-12	2021-09-13
12	11	Milk	semi skimmed milk	2ltr	member b	2	2021-09-12	2021-07-12	2021-09-13
13	22	Milk	semi skimmed milk	1ltr	member a	3	2019-07-12	2019-07-12	2019-09-13
14	22	Milk	semi skimmed milk	1ltr	member a	6	2019-08-12	2019-07-12	2019-09-13
15	22	Milk	semi skimmed milk	1ltr	member a	30	2019-09-12	2019-07-12	2019-09-13
16	22	Milk	semi skimmed milk	1ltr	member b	50	2019-07-12	2019-07-12	2019-09-13
17	22	Milk	semi skimmed milk	1ltr	member b	10	2019-08-12	2019-07-12	2019-09-13
18	22	Milk	semi skimmed milk	1ltr	member b	10	2019-09-12	2019-07-12	2019-09-13
19	22	Milk	semi skimmed milk	2ltr	member a	20	2019-07-12	2019-07-12	2019-09-13
20	22	Milk	semi skimmed milk	2ltr	member a	12	2019-08-12	2019-07-12	2019-09-13
21	22	Milk	semi skimmed milk	2ltr	member a	24	2019-09-12	2019-07-12	2019-09-13
22	22	Milk	semi skimmed milk	2ltr	member b	44	2019-07-12	2019-07-12	2019-09-13
23	22	Milk	semi skimmed milk	2ltr	member b	2	2019-08-12	2019-07-12	2019-09-13
24	22	Milk	semi skimmed milk	2ltr	member b	21	2019-09-12	2019-07-12	2019-09-13