核心思想就是减少对表的多次扫描，最好减成一次。 创建测试表 createtablet1asselectfromdba_objects; createindexind_object_idont1(object_id); createindexind_object_nameont1(object_name); createindexind_owneront1(owner); createindexind_object_typeont1(object_type); createtablet2asselectfromcdb_objects; createindexind_object_id_2...