使用表关联去做
# Write your MySQL query statement below
SELECT T1.NAME AS CUSTOMERS
FROM Customers T1 LEFT JOIN ORDERS T2
ON T1.ID=T2.CUSTOMERID
WHERE T2.ID = 'null'
为什么是错的?
因为应该用 where T2.ID is null
使用表关联去做
# Write your MySQL query statement below
SELECT T1.NAME AS CUSTOMERS
FROM Customers T1 LEFT JOIN ORDERS T2
ON T1.ID=T2.CUSTOMERID
WHERE T2.ID = 'null'
为什么是错的?
因为应该用 where T2.ID is null
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