力扣資料庫 183 從不訂購的客戶

create

table
ifnot
exists customers (id int
, name varchar
(255))
create
table
ifnot
exists orders (id int
, customerid int
)truncate
table customers
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'
)truncate
table orders
insert
into orders (id, customerid)
values
('1'
,'3'
)insert
into orders (id, customerid)
values
('2'
,'1'
)

customers表：

+----+-------+

| id | name |
+----+-------+
| 1 | joe |
| 2 | henry |
| 3 | sam |
| 4 | max |
+----+-------+

+----+------------+

| id | customerid |
+----+------------+
| 1 | 3 |
| 2 | 1 |
+----+------------+

+-----------+

| customers |
+-----------+
| henry |
| max |
+-----------+

方法1：使用 not in + 子查詢

select c.name  as customers

from customers as c 
where c.id notin(
select customerid from orders
)

方法2：使用left join

select c.name as customers

from customers as c 
left
join orders as o
on c.id = o.customerid
where o.id is
null

力扣183 從不訂購的客戶

力扣183.從不訂購的客戶 某 包含兩個表，customers 表和 orders 表。編寫乙個 sql 查詢，找出所有從不訂購任何東西的客戶。customers 表 id name 1 joe 2 henry 3 sam 4 max orders 表 id customerid 1 3 2 1 例...

LeetCode 183 從不訂購的客戶

題意 某 包含兩個表，customers 表和 orders 表。編寫乙個 sql 查詢，找出所有從不訂購任何東西的客戶。customers 表 id name 1 joe 2 henry 3 sam 4 max orders 表 id customerid 1 3 2 1 例如給定上述 你的查詢應...

資料庫題目 從不訂購的客戶

某 包含兩個表，customers 表和 orders 表。編寫乙個 sql 查詢，找出所有從不訂購任何東西的客戶。customers 表 id name 1 joe 2 henry 3 sam 4 max orders 表 id customerid 1 3 2 1 例如給定上述 你的查詢應返回 ...