力扣sql中等篇练习(十一)

1 好友申请|| :谁有最多的好友

1.1 题目内容

1.1.1 基本题目信息

1.1.2 示例输入输出

1.2 示例sql语句

# 出现数字次数越多,就代表它的好友越多
# 对两列数据合并时 不取出合并数据,采用UNION ALL
SELECT t1.id,count(*) num
FROM
(
    SELECT requester_id id
    FROM RequestAccepted
    UNION ALL
    SELECT accepter_id id
    FROM RequestAccepted
)t1
GROUP BY t1.id
ORDER BY count(*) desc
limit 1

1.3 运行截图

2 平面上的最近距离

2.1 题目内容

2.1.1 基本题目信息

2.1.2 示例输入输出

2.2 示例sql语句

# Write your MySQL query statement below
SELECT distinct ROUND(sqrt(power(p1.x-p2.x,2)+power(p1.y-p2.y,2)),2) shortest 
FROM Point2D p1
cross JOIN Point2D p2
on concat(p1.x,p1.y) <> concat(p2.x,p2.y)
ORDER BY shortest  asc
limit 0,1;

2.3 运行截图

3 二级关注者

3.1 题目内容

3.1.1 基本题目信息

3.1.2 示例输入输出

3.2 示例sql语句

# Write your MySQL query statement below

SELECT followee follower,count(*) num
FROM follow
WHERE followee in
(
    SELECT distinct follower
    FROM follow
)
GROUP BY followee 
ORDER BY follower asc

3.3 运行截图