distinct

SELECT e.Department_Id , d.Department_Name 

  FROM departments d inner join employees e 

  ON e.department_id = d.department_id; 

 

Inner join으로 가져왔떤거다 이걸 27개의 로우로 만들게 중복을 제거하여보자 

 

SELECT distinct e.Department_Id , d.Department_Name 

  FROM departments d inner join employees e 

  ON e.department_id = d.department_id; 

 

 

이런 실제로 활용된파트는 10번부터 100번까지 밖에 안써서 11개의 칼럼만 나왔다 

나머지들은 안나왔다 허엉