力扣sql中等篇练习(七)

1 查询活跃业务

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

# Write your MySQL query statement below
# 先求出所有业务的平均发生次数
SELECT t2.business_id
FROM
(
    SELECT e.*,IF(e.occurences>t1.A_NUM,1,0) total
    FROM Events e
    INNER JOIN
    (
        SELECT event_type,AVG(occurences) A_NUM
        FROM Events
        GROUP BY event_type
    )t1
    ON e.event_type=t1.event_type
)t2
GROUP BY business_id
HAVING SUM(t2.total)>=2

1.3 运行截图

2 活跃用户

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

# 连续天数可以考虑自连接+分组筛选的方法
SELECT id,name
FROM Accounts
WHERE id in
(
    SELECT L1.id
    FROM Logins L1
    INNER JOIN Logins L2
    ON L1.id=L2.id AND DATEDIFF(L1.login_date,L2.login_date) between 0 AND 4
    GROUP BY L1.id,L1.login_date
    HAVING count(distinct L2.login_date)=5
)
ORDER BY id asc

2.3 运行截图

3 至少有五名直接下属的经理

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

# ①先找到经理的 ②根据数量去进行分组晒选 ③筛选后的就是经理
# 注意 需要避免none值的影响
SELECT name
FROM Employee
WHERE id in
(
    SELECT managerId
    FROM Employee
    WHERE managerId !='None'
    GROUP BY managerId
    HAVING count(*)>=5
)

3.3 运行截图