sql求大神解决

with A_CODE as
 (select 'JACK' namea, '2' a, '1' b    from dual
  union all
  select 'JACK' namea, '3' a, '2' b    from dual
  union all
  select 'JACK' namea, '1' a, '3' b    from dual
  union all
  select 'TOM' namea, '1' a, '1' b    from dual
  union all
  select 'TOM' namea, '2' a, '2' b    from dual
  union all
  select 'TOM' namea, '4' a, '3' b    from dual
  union all
  select 'SAM' namea, '2' a, '1' b    from dual
  union all
  select 'SAM' namea, '2' a, '2' b from dual)

根据namea分组 求a/b 的值分别在0-1和1-2的列count值 plsql SQL
[解决办法]
这样？

with A_CODE as
 (select 'JACK' namea, '2' a, '1' b
    from dual
  union all
  select 'JACK' namea, '3' a, '2' b
    from dual
  union all
  select 'JACK' namea, '1' a, '3' b
    from dual
  union all
  select 'TOM' namea, '1' a, '1' b
    from dual
  union all
  select 'TOM' namea, '2' a, '2' b
    from dual
  union all
  select 'TOM' namea, '4' a, '3' b
    from dual
  union all
  select 'SAM' namea, '2' a, '1' b
    from dual 
 
  union all
  select 'SAM' namea, '2' a, '2' b from dual)
select namea,
       sum(case
             when a between 0 and 1 then
              1
             else
              0
           end) a,
       sum(case
             when b between 1 and 2 then
              1
             else
              0
           end) b
  from a_code
 group by namea;