数据表信息:

数据表如图:

有用户表行为记录表t_act_records表，包含两个字段：uid（用户ID），imp_date（日期）

话不多说, 再看需求~

需求:

编写一个 sql 查询，计算2021年每个月，每个用户连续登录的最多天数?

sql 复制代码

select 
    uid, 
    date_format(imp_date, '%y-%m') as month,
    max(consecutive_days) as max_consecutive_days
from (
    select 
        uid,
        imp_date,
        row_number() over (partition by uid, date_format(imp_date, '%y-%m') order by imp_date) -
        row_number() over (partition by uid, date_format(imp_date, '%y-%m') order by imp_date) as consecutive_days
    from t_act_records
    where year(imp_date) = 2021
) as subquery
group by uid, month;

编写一个 sql 查询，计算2021年每个月，连续2天都有登录的用户名单?

sql 复制代码

select distinct uid, date_format(imp_date, '%y-%m') as month
from t_act_records
where year(imp_date) = 2021
group by uid, date_format(imp_date, '%y-%m')
having count(distinct imp_date) >= 2;

编写一个 sql 查询，计算2021年每个月，连续5天都有登录的用户数?

sql 复制代码

select
    date_format(imp_date, '%y-%m') as month,
    count(distinct uid) as user_count
from (
    select
        uid,
        imp_date,
        row_number() over (partition by uid, date_format(imp_date, '%y-%m') order by imp_date) -
        row_number() over (partition by uid, date_format(imp_date, '%y-%m') order by imp_date) as consecutive_days
    from t_act_records
    where year(imp_date) = 2021
) as subquery
where consecutive_days <= 5
group by month;

最后给大家介绍一下我这边的创建数据表和插入数据的操作步骤, 想要自己测试的话, 可以参考:

sql 复制代码

DROP TABLE if EXISTS t_act_records;
CREATE TABLE t_act_records
(uid  VARCHAR(20),
imp_date DATE);

INSERT INTO t_act_records VALUES('u1001', 20210101);
INSERT INTO t_act_records VALUES('u1002', 20210101);
INSERT INTO t_act_records VALUES('u1003', 20210101);
INSERT INTO t_act_records VALUES('u1003', 20210102);
INSERT INTO t_act_records VALUES('u1004', 20210101);
INSERT INTO t_act_records VALUES('u1004', 20210102);
INSERT INTO t_act_records VALUES('u1004', 20210103);
INSERT INTO t_act_records VALUES('u1004', 20210104);
INSERT INTO t_act_records VALUES('u1004', 20210105);