Level 0 実行計画(Query Plan)の読み方 以下のようなSQLの実行計画を取得してみる。
UPDATE T_ITEM_INBOUND t3 SET status_flag = '9' , updated_datetime = CURRENT_TIMESTAMP , updated_by = 'APP_001' FROM ( SELECT t1.group_num , t1.level3_item_code FROM T_ITEM_INBOUND t1 WHERE t1.status_flag = '1' AND t1.group_num = '10' AND t1.level3_item_code = '1000-2000-3000' GROUP BY t1.group_num , t1.level1_item_code , t1.level2_item_code , t1.level3_item_code , t1.color_code , t1.size_code , t1.pattern_length_code HAVING 1 < COUNT(t1.group_num) ) t2 WHERE t3.status_flag = '1' AND t3.group_num = t2.group_num AND t3....