1.选择

1.力扣595.大的国家

i.

1 # Write your MySQL query statement below
2 select name,population,area from World 
3 where area >= 3000000 or population >= 25000000;

ii.

 1 # Write your MySQL query statement below
 2 select 
 3    name,population,area 
 4 from 
 5    World 
 6 where 
 7    area >= 3000000
 8 
 9 UNION
10 
11 select 
12    name,population,area 
13 from 
14    World 
15 where 
16    population >= 25000000;

 2.力扣1757.可回收且低脂的产品

1 # Write your MySQL query statement below
2 SELECT 
3    product_id
4 FROM
5    Products
6 WHERE
7    low_fats = 'Y' AND recyclable = 'Y';

3.力扣584.寻找用户推荐人

i.

1 # Write your MySQL query statement below
2 SELECT 
3    name
4 FROM
5    customer 
6 WHERE
7    id NOT IN(SELECT id FROM customer WHERE referee_id = 2);

ii.

注：不可以 referee_id = NULL 这样写

1 # Write your MySQL query statement below
2 SELECT 
3    name
4 FROM
5    customer 
6 WHERE
7    referee_id <> 2 OR referee_id IS NULL;

4.力扣183.从不订购的客户

1 # Write your MySQL query statement below
2 SELECT
3    name /* as */ Customers
4 FROM
5    Customers
6 WHERE
7    Id NOT IN(SELECT CustomerId FROM Orders);

 

posted @ 2022-08-02 10:58  balabalahhh  阅读(32)  评论(0)    收藏  举报