게으른 엔지니어

테이블 정의

create table proj (

  task_id varchar2(3),

  based_on varchar2(3),

  task_in_charge varchar2(10)

);

데이터 삽입

insert into proj values('P01', '', 'KING');

insert into proj values('P02', 'P01', 'KOCHAR');

insert into proj values('P03', '', 'GREEN');

insert into proj values('P04', 'P03', 'SCOTT');

OUTER JOIN 쿼리 수행

SELECT p.task_id, p.based_on, d.task_in_charge

FROM proj p FULL OUTER JOIN proj d

ON (p.based_on = d.task_id);

SELECT p.task_id, p.based_on, d.task_in_charge

FROM proj p LEFT OUTER JOIN proj d

ON (p.based_on = d.task_id);

SELECT p.task_id, p.based_on, d.task_in_charge

FROM proj p RIGHT OUTER JOIN proj d

ON (p.based_on = d.task_id);

결과