Привет, попробуйте пример ниже.
DECLARE @tblClient AS TABLE (ID INT , Name varchar(100))
DECLARE @tblClientSub As TABLE (id INT,client_id INT,date_sub DATE,sub_price INT)
INSERT INTO @tblClient (id,Name)
VALUES
(1,'Linda'),
(2,'Mary'),
(3,'Joe')
INSERT INTO @tblClientSub(Id,client_id , date_sub , sub_price)
VALUES
(1,1,'2018/01/01',50),
(2,2,'2018/02/01',50),
(3,2,'2018/03/01',30),
(4,2,'2018/04/01',30),
(5,3,'2018/01/01',50),
(6,3,'2018/07/01',50),
(7,1,'2018/02/01',40)
SELECT c.Id,c.Name,cs.date_sub,cs.sub_price
FROM @tblClient c
CROSS APPLY (SELECT TOP (1)date_sub,sub_price
FROM @tblClientSub
WHERE client_id = c.Id
ORDER BY date_sub DESC) cs