postgresql 계층형 쿼리
CREATE TABLE BOM( ITEM_ID INTEGER NOT NULL, PARENT_ID INTEGER, ITEM_NAME CHARACTER VARYING(20) NOT NULL, ITEM_QTY INTEGER, CONSTRAINT BOM_KEY PRIMARY KEY (ITEM_ID) ); INSERT INTO BOM VALUES (1001, null, ‘컴퓨터’, 1); INSERT INTO BOM VALUES (1002, 1001, ‘본체’, 1); INSERT INTO BOM VALUES (1003, 1001, ‘모니터’, 1); INSERT INTO BOM VALUES (1004, 1001, ‘프린터’, 1); INSERT INTO BOM VALUES (1005, 1002, ‘메인보드’, ..
