7-4-4. 여러 테이블의 조인 힌트

-- [SQL-7-4-4-a]

EXPLAIN (COSTS OFF)
SELECT  /*+ Leading(((t1 t2) t3)) */
        *
FROM    startdbpg.ms_shop t1
        INNER JOIN startdbpg.tr_ord t2 ON (t1.shop_id = t2.shop_id)
        INNER JOIN startdbpg.tr_ord_det t3 ON (t3.ord_no = t2.ord_no);
SQL
복사

-- [SQL-7-4-4-b]

EXPLAIN (COSTS OFF)
SELECT  /*+ Leading(((t1 t2) t3)) NestLoop(t1 t2) NestLoop(t1 t2 t3) */
        *
FROM    startdbpg.ms_shop t1
        INNER JOIN startdbpg.tr_ord t2 ON (t1.shop_id = t2.shop_id)
        INNER JOIN startdbpg.tr_ord_det t3 ON (t3.ord_no = t2.ord_no);
SQL
복사

-- [SQL-7-4-4-c]

EXPLAIN (COSTS OFF)
SELECT  /*+ Leading((t3 (t2 t1))) NestLoop(t2 t1) HashJoin(t3 t2 t1) */
        *
FROM    startdbpg.ms_shop t1
        INNER JOIN startdbpg.tr_ord t2 ON (t1.shop_id = t2.shop_id)
        INNER JOIN startdbpg.tr_ord_det t3 ON (t3.ord_no = t2.ord_no);
SQL
복사