Postgres 15

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CREATE TABLE client_contracts (
  id bigint PRIMARY KEY
, client_id bigint NOT NULL
, name varchar
, autopay_status varchar
, contract_id integer
, start_date date
, end_date date
);

INSERT INTO client_contracts(id, client_id, name, autopay_status, contract_id, start_date, end_date)
VALUES
  ( 1,1,'Contract 1','Inactive',1111,'2019-08-30','2020-02-29')
, ( 2,1,'Contract 1','Inactive',1112,'2020-02-29','2020-08-29')
, ( 3,1,'Contract 1','Active'  ,1113,'2020-08-29','2021-02-28')
, ( 4,2,'Contract 2','Inactive',2221,'2019-08-30','2020-02-29')
, ( 5,2,'Contract 2','Inactive',2222,'2020-02-29','2020-08-29')
, ( 6,2,'Contract 2','Active'  ,2223,'2020-08-29','2021-02-28')
, ( 7,3,'Contract 3','Inactive',3331,'2019-08-30','2020-02-29')
, ( 8,3,'Contract 3','Inactive',3332,'2020-03-29','2020-09-29')
, ( 9,3,'Contract 3','Inactive',3333,'2020-09-29','2021-03-28')
, (10,3,'Contract 3','Inactive',3334,'2021-04-28','2021-10-28')
, (11,3,'Contract 3','Inactive',3335,'2021-10-28','2022-04-28')
, (12,3,'Contract 3','Active'  ,3336,'2022-04-28','2022-10-28')
;

CREATE TABLE

INSERT 0 12

client_id	start_date	end_date	continous_contract	contract_days	contract_nr	sum_days
1	2019-08-30	2020-02-29	t	183	0	183
1	2020-02-29	2020-08-29	t	182	0	365
1	2020-08-29	2021-02-28	t	183	0	548
2	2019-08-30	2020-02-29	t	183	0	183
2	2020-02-29	2020-08-29	t	182	0	365
2	2020-08-29	2021-02-28	t	183	0	548
3	2019-08-30	2020-02-29	t	183	0	183
3	2020-03-29	2020-09-29	f	184	1	184
3	2020-09-29	2021-03-28	t	180	1	364
3	2021-04-28	2021-10-28	f	183	2	183
3	2021-10-28	2022-04-28	t	182	2	365
3	2022-04-28	2022-10-28	t	183	2	548

SELECT 12