排列组合查询算法

[死不回头]

例如有几种药物,a,b,c,d,e......;有一个配伍禁忌的表，就是那两种药不能在一起使用，表的名字比如叫 table，里面列为：药品1，药品2，配伍禁忌说明。
用啥算法能最快的查出a,b,c,d,e.....，左右的可能配伍禁忌（在table中定义好的）

[js14982]

with t as
(select 'a' id from dual union all
select 'b' id from dual union all
select 'c' id from dual union all
select 'd' id from dual union all
select 'e' id from dual 
), table1 as
(
select 'a' id1,'e' id2,null jj from dual union all
select 'b' id1,'f' id2,null jj from dual 
)
select 
     c.*
from t a,t b ,table1 c
where a.id = c.id1
  and b.id = c.id2
;