MySQL Interview Questions: Detailed Explanation of User Amount Recharge Interview Questions

Today we continue to organize MySQL interview questions, today's topic is related to user recharge amount

According to the title, let's create a table

create table user_log(login_date date comment 'login date',user_id int comment 'user id');create table payment_log(order_id int primary key auto_increment comment 'order number',pay_date date comment 'payment date',user_id int comment 'user id',revenue int comment 'recharge amount');

Next, for a better demonstration, let's fill in the data

insert into user_log values('2022-03-11', 10),('2022-03-19', 10),('2022-03-21', 10),('2022-03-22', 10),('2022-03-25', 10),('2022-03-29', 10),('2022-04-11', 10),('2022-04-13', 10),('2022-04-17', 10),('2022-03-10', 20),('2022-03-11', 20),('2022-03-14', 20),('2022-03-16', 20),('2022-03-20', 20),('2022-04-11', 20),('2022-04-13', 20),('2022-04-17', 20),('2022-04-21', 20),('2022-05-01', 20);insert into payment_log(pay_date, user_id, revenue) values('2022-03-11', 10, 30),('2022-03-11', 10, 30),('2022-03-11', 10, 30),('2022-03-11', 10, 30),('2022-03-19', 10, 50),('2022-03-19', 10, 50),('2022-03-21', 10, 100),('2022-03-21', 10, 100),('2022-03-21', 10, 100),('2022-03-22', 10, 20),('2022-03-22', 10, 20),('2022-03-25', 10, 10),('2022-03-29', 10, 10),('2022-04-11', 10, 70),('2022-04-11', 10, 70),('2022-04-13', 10, 80),('2022-04-17', 10, 90),('2022-03-10', 20, 90),('2022-03-11', 20, 80),('2022-03-14', 20, 60),('2022-03-16', 20, 120),('2022-03-20', 20, 99),('2022-04-11', 20, 87),('2022-04-13', 20, 53),('2022-04-17', 20, 56),('2022-04-21', 20, 77),('2022-05-01', 20, 32),('2022-03-10', 20, 29),('2022-03-11', 20, 30),('2022-03-14', 20, 18),('2022-03-16', 20, 6),('2022-03-20', 20, 19),('2022-04-11', 20, 21),('2022-04-13', 20, 20),('2022-04-17', 20, 76),('2022-04-21', 20, 82),('2022-05-01', 20, 91);

Everything is ready, let's complete the requirements

/*Requirement 1: Extract the daily accumulated recharge amount of each userRequirement 2: Extract the recharge amount of each user's last 7-day login*/-- Extract the daily accumulated recharge amount of each user/*Idea: In payment_log, group the amount by user and date*/select user_id, pay_date, sum(revenue) as recharge amountfrom payment_log group by user_id, pay_date;-- Extract the recharge amount of each user's last 7-day login/*To get the corresponding data, we need to connect the queryWe connect the daily reset amount of each user above with the user table*/select t.*, login_date,row_number() over(partition by user_id order by login_date desc) rankingfrom (select user_id, pay_date, sum(revenue) as recharge amountfrom payment_log group by user_id, pay_date) as t join user_logon t.user_id=user_log.user_id and pay_date=login_date;-- Based on this data, find the top 7 and then count the recharge amount of each userselect user_id, sum (recharge amount) from(select t.*, login_date,row_number() over(partition by user_id order by login_date desc) rankingfrom (select user_id, pay_date, sum(revenue) as recharge amountfrom payment_log group by user_id, pay_date) as t join user_logon t.user_id=user_log.user_id and pay_date=login_date) as t1where ranking < 8 group by user_id;

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