大数据第36天—Mysql练习题7-杨大伟

需求：某网站包含两个表，Customers 表和 Orders 表。编写一个 SQL 查询，找出所有从不订购任何东西的客户。

展示效果：

Customers

Henry

Max

Create table If Not Exists Customers (Id int, Name varchar(255));
Create table If Not Exists Orders (Id int, CustomerId int);

insert into Customers (Id, Name) values (1, 'Joe');
insert into Customers (Id, Name) values (2, 'Henry');
insert into Customers (Id, Name) values (3, 'Sam');
insert into Customers (Id, Name) values (4, 'Max');

insert into Orders (Id, CustomerId) values (1, 3);
insert into Orders (Id, CustomerId) values (2, 1);

最终SQL:

select 
     customers.name as 'Customers'
from 
     customers
where 
     customers.id not in(
        select
              customerid 
        from 
              orders
     );