sap_task4:

CREATE TABLE INTERNET (
  PUR_DATE DATE,
  IM VARCHAR(100),
  SKD INT,
  PRICE INT
);
INSERT INTO INTERNET (PUR_DATE, IM, SKD, PRICE)
VALUES
    ('2021-02-02',	'ZOOSHOP',	1,	5000),
    ('2021-02-04',	'ZOOSHOP',	1,	5000),
    ('2021-02-05',	'ZOOSHOP',	2,	3700),
    ('2021-02-08',	'ZOOSHOP',	2,	3700),
    ('2021-02-09',	'ZOOSHOP',	3,	1800),
    ('2021-02-13',	'PROMARKET',	1,	5000),
    ('2021-02-14',	'PROMARKET',	4,	2200);

SELECT (SELECT SUM(PRICE)
        FROM INTERNET
        WHERE PUR_DATE <= T1.PUR_DATE) COSTS
FROM INTERNET T1
ORDER BY IM, PUR_DATE
OFFSET 1 ROWS FETCH NEXT 1 ROWS ONLY;