看看这个方法能不能帮助你打开思路解决问题：

with t1 as (

select '用户A' as user_name,'管理员' as role_name,'123' as other from dual union all

select '用户A' as user_name,'用户主管' as role_name,'456' as other from dual union all

select '用户A' as user_name,'用户经理' as role_name,'789' as other from dual

),

t2 as (

select '权限大小第1' as role_order,'管理员' as role_name from dual union all

select '权限大小第2' as role_order,'用户主管' as role_name from dual union all

select '权限大小第3' as role_order,'用户经理' as role_name from dual

),

t3 as (

select t1.user_name,

       t1.role_name,

       t1.other,

       t2.role_order,

       row_number() over(partition by t1.user_name order by t2.role_order asc) as rn

  from t1 left join t2 on (t2.role_name = t1.role_name)

)

select * from t3 where t3.rn = 1;

你这个用汉字举例，说得有问题，有三个角色，然后知道是管理员，但是假如另一个用户的角色是：    用户主管，用户总监，用户总经理，，用汉字判断不了哪一个角色是最高的呀。你得有一个对照的表才可以。至少要有一个表里面可以标识出来，这样查询的时候就可以判断