[Solvesql] 멘토링 짝꿍 리스트

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

solvesql

 

SELECT
  a.employee_id mentee_id, a.name mentee_name, b.employee_id mentor_id, b.name mentor_name
FROM
  employees a
  left outer join employees b on a.department <> b.department
WHERE
  a.join_date > '2021-10-01'
  and b.join_date < '2020-01-01'
ORDER by
  mentee_id, mentor_id