[SQL문제풀기] 멘토링 짝꿍 리스트

문제

solvesql.com

https://solvesql.com/problems/mentor-mentee-list/

SQLite

내가 작성한 정답

with ee as (select employee_id, name, department
            from employees
            where join_date >= date('2021-12-31','-3 month') ),
      o as ( select employee_id, name, department
             from employees
             where join_date <= date('2021-12-31','-2 year'))
select e.employee_id mentee_id, e.name mentee_name,
        o.employee_id mentor_id, o.name mentor_name
from ee e 
left join o o on e.department <> o.department
order by 1, 3;