比巴卜和哪步卜

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题解 | 获取员工其当前的薪水比其manager当前薪水还高的相关信息

# 连接表:经理工资表+员工工资表 # 用自己薪资减去老板薪资，如果大于0就选择 # 员工工资表 select a.emp_no as emp_no, b.manager_no as manager_no, a.emp_salary as emp_salary, b...

2026-01-04

0 19

题解 | 获取当前薪水第二多的员工的emp_no以及其对应的薪水salary

select e.emp_no, s.salary, e.last_name, e.first_name from employees as e inner join # 第二步，连接两张表 salaries as s on e...

2026-01-04

0 17

题解 | 21年8月份练题总数

select count(distinct device_id) as did_cnt, count(*) as question_cnt from question_practice_detail where substring(date,1,7)='2021-08...

2026-01-03

0 20

题解 | 电话号码格式校验

select * from contacts where left(phone_number,1) != 0 and case when phone_number like '%-%' then length(substring_in...

2026-01-03

0 31

题解 | 统计复旦用户8月练题情况

select device_id, a.university as university, count(if(month(a.date)=08,1,null)) as question_cnt, count(if(a.result='right' and month(...

2026-01-03

0 19

题解 | 计算25岁以上和以下的用户数量

# 筛选出25岁以上和25岁以下的人，统计人数。 select '25岁以下' as age_cut,count(device_id) as number from user_profile where age<25 or age is Null union sel...

2026-01-02

0 16