用SQL得到全排列

[sql]代码库

create table #users (name char(2),value char(1),id number);
insert into #users values('甲','a',1);
insert into #users values('乙','b',2);
insert into #users values('丙','c',3);
insert into #users values('丁','d',4);
commit;
--2个元素全排列
select o.p as "排列" from
  (select replace (sys_connect_by_path( value, ',' ) , ',' ) p
  from #users connect by nocycle value != prior value) o
  where length(o.p) =2;
--3个元素全排列
select o.p as "排列" from
  (select replace (sys_connect_by_path( value, ',' ) , ',' ) p
  from #users connect by nocycle value != prior value) o
  where length(o.p) =3;
--4个元素全排列
select o.p as "排列" from
  (select replace (sys_connect_by_path( value, ',' ) , ',' ) p
  from #users connect by nocycle value != prior value) o
  where length(o.p) =4;