我怎樣才能使用子查詢重現此？

Question

我剛剛開始學習SQL，並已被分配重新使用子查詢的任務，但我已經搜索了一下，仍然無法理解如何做到這一點。任何幫助，將不勝感激:)

SELECT ORDER_NUMB, ORDER_DATE FROM BRIAN.ORDERS 
INNER JOIN BRIAN.CUSTOMERS 
ON BRIAN.ORDERS.CUSTOMER_NUMB=BRIAN.CUSTOMERS.CUSTOMER_NUMB 
WHERE CUSTOMER_FIRST_NAME = 'Peter' 
AND CUSTOMER_LAST_NAME = 'Johnson'; 

Answer 1

你應該在子查詢中選擇彼得約翰遜客戶，並篩選。

SELECT ORDER_NUMB 
    , ORDER_DATE 
FROM BRIAN.ORDERS 
WHERE BRIAN.ORDERS.CUSTOMER_NUMB IN (SELECT BRIAN.CUSTOMERS.CUSTOMER_NUMB 
           FROM BRIAN.CUSTOMERS 
           WHERE CUSTOMER_FIRST_NAME = 'Peter' 
           AND CUSTOMER_LAST_NAME = 'Johnson')