[DATABASE/ORACLE] START WITH ~ CONNECT BY PRIOR 절 : 재귀 호출하기

icodebroker ORACLE 2024-06-18

■ START WITH ~ CONNECT BY PRIOR 절을 사용해 재귀 호출하는 방법을 보여준다.

▶ 예제 코드 (SQL)


CREATE TABLE MENU
(
    ID        INT
   ,PARENT_ID INT
   ,NAME      VARCHAR(50)
);

INSERT INTO MENU VALUES (1, 0, '메뉴1');
INSERT INTO MENU VALUES (2, 0, '메뉴2');
INSERT INTO MENU VALUES (3, 1, '메뉴3');
INSERT INTO MENU VALUES (4, 1, '메뉴4');
INSERT INTO MENU VALUES (5, 1, '메뉴5');
INSERT INTO MENU VALUES (6, 5, '메뉴6');
INSERT INTO MENU VALUES (7, 2, '메뉴7');
INSERT INTO MENU VALUES (8, 2, '메뉴8');

SELECT LPAD(' ', 2 * (LEVEL - 1)) || NAME AS NAME
FROM   MENU
START WITH PARENT_ID = 0
CONNECT BY PRIOR ID  = PARENT_ID;

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CREATE TABLE MENU

(

ID INT

,PARENT_ID INT

,NAME VARCHAR(50)

);

INSERT INTO MENU VALUES (1, 0, '메뉴1');

INSERT INTO MENU VALUES (2, 0, '메뉴2');

INSERT INTO MENU VALUES (3, 1, '메뉴3');

INSERT INTO MENU VALUES (4, 1, '메뉴4');

INSERT INTO MENU VALUES (5, 1, '메뉴5');

INSERT INTO MENU VALUES (6, 5, '메뉴6');

INSERT INTO MENU VALUES (7, 2, '메뉴7');

INSERT INTO MENU VALUES (8, 2, '메뉴8');

SELECT LPAD(' ', 2 * (LEVEL - 1)) || NAME AS NAME

FROM MENU

START WITH PARENT_ID = 0

CONNECT BY PRIOR ID = PARENT_ID;