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select e.Name as Employee
from Employee as e join Employee as m on m.Id = e.ManagerId
where e.Salary > m.Salary
위 코드에서 e는 Joe, Henry 만 남아있고(join의 결과 managerID == ID)
m은 Sam, Max만 존재하는 것이다.
self join
www.w3schools.com/sql/sql_join_self.asp
SQL Self Join
SQL Self Join SQL Self Join A self join is a regular join, but the table is joined with itself. Self Join Syntax SELECT column_name(s) FROM table1 T1, table1 T2 WHERE condition; T1 and T2 are different table aliases for the same table. Demo Database In thi
www.w3schools.com
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