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全部文章（共9篇）

题解 | #最后一个匹配上的位置#

select device_id, (char_length(nick_name) - char_length(substring_index(nick_name,'abc',-1)) - char_length('abc') + 1) as last_idx, concat('abc',subs...

2023-09-19

0 194

题解 | #筛选出学校名中包含特定关键词的用户#

select id,device_id,university from user_profile where (university like '北京%' or university like '上海%' ) and (university like '%学院' or universit...

2023-09-18

0 274

题解 | #牛客每个人最近的登录日期(四)#

# 找到每个用户第一次登录的时间使用左连接进行计数 select l.date,count(distinct h.user_id) as new from login l left join (select user_id,min(date) date from login group by u...

2023-08-04

0 243

题解 | #牛客每个人最近的登录日期(三)#

# 根据mindate 与 user_id 进行匹配 select round( (select count(*) from login l inner join (select user_id,min(date) date from login group by user_id) as h o...

2023-08-04

0 305

题解 | #统计salary的累计和#

select emp_no,salary,sum(salary) over (order by emp_no) as running_total from salaries where to_date ='9999-01-01' 窗口函数的使用sum(a) over (order by b) 的含...

2023-08-04

3 230

题解 | #获取有奖金的员工相关信息。#

select e.emp_no,e.first_name,e.last_name,e1.btype,s.salary, round((case e1.btype when 1 then s.salary*0.1 when 2 then s.salary*0.2 else s.salary*0.3 e...

2023-08-04

0 287

题解 | #实习广场投递简历分析(二)#

select job,left(date,7) as mon,sum(num) as cnt from resume_info where date between '2025-01-01' and '2025-12-31' group by job,left(date,7) order by ...

2023-08-03

0 257

题解 | #找出没有分类的电影id以及名称#

SELECT f.film_id, f.title FROM film AS f LEFT JOIN film_category AS fc ON f.film_id = fc.film_id WHERE category_id IS NULL;

2023-08-02

0 368

题解 | #分组计算练习题#

select gender ,university , count(*) as user_num ,round(avg(active_days_within_30),1) as avg_active_day ,round(avg(question_cnt) ,1) as avg_question_c...

2023-07-29

0 267