您可以使用 row_number() &做聚合:

You can use row_number() & do aggregation :

select User, 
       max(case when seq = 1 then role end) as a,
       max(case when seq = 2 then role end) as b,
       max(case when seq = 3 then role end) as c
from (select t.*,
             row_number() over (partition by User order by group) as seq
      from table t
     ) t
group by User;