Leetcode183 Customers Who Never Order

Posted on 2020-02-22 In 数据库 Valine:

Problem:

Solution:

#左外链接

SELECT
    C.Name AS Customers
FROM
    Customers C
    LEFT JOIN Orders O
    ON C.Id = O.CustomerId
WHERE
    O.CustomerId IS NULL;
#子查询

SELECT
    Name AS Customers
FROM
    Customers
WHERE
    Id NOT IN ( 
        SELECT CustomerId 
        FROM Orders 
    );