Oracle SQL 排序兩個相互連接的列值

Question

我的表如下

CC1  CC2
675  876
123  987
453  123
876  453
987  432

想要的結果

CC1  CC2
675  876
876  453
453  123
123  987
987  432

Answer 1

sql分層查詢

SELECT employee_id, last_name, manager_id
   FROM employees
   CONNECT BY PRIOR employee_id = manager_id;

參考https://docs.oracle.com/database/121/SQLRF/queries003.htm#SQLRF52335

Answer 2

您需要使用分層查詢作為

select cc1 , cc2 
  from tab
 start with cc1 = 675
connect by prior cc2 = cc1;

演示

更新：是的，您提供的是動態確定根的良好關系，或者

select * 
  from tab 
 start with CC1 = (select CC1 
                     from tab t 
                    where not exists (select CC1
                                        from tab
                                       where CC2 = t.CC1 )) 
connect by prior CC2 = CC1

也是可以的。