已知原表數據如下：

要求實現如下效果：

--創建表
create table tmp as
select ‘火腿腸‘ c1, ‘銷售一部‘ c2,‘老王‘   c3, 1.5 c4 from dual union all
select ‘玉米‘   c1, ‘銷售五部‘ c2,‘B老劉‘  c3, 1   c4 from dual union all
select ‘筆記本‘ c1, ‘銷售一部‘ c2,‘老王‘   c3, 3   c4 from dual union all
select ‘筆記本‘ c1, ‘銷售七部‘ c2,‘老張‘   c3, 3   c4 from dual union
 
 all
select ‘桌子‘   c1, ‘銷售九部‘ c2,‘老孫‘   c3, 4   c4 from dual union all
select ‘火腿腸‘ c1, ‘銷售五部‘ c2,‘老劉‘   c3, 1.5 c4 from dual union all
select ‘火腿腸‘ c1, ‘銷售四部‘ c2,‘老趙‘   c3, 1.5 c4 from dual union all
select ‘玉米‘   c1, ‘銷售四部‘ c2,‘老李‘   c3, 1   c4 from dual union all
select ‘筆記本‘ c1, ‘銷售七部‘ c2,‘老張‘   c3, 3
 
   c4 from dual union all
select ‘玉米‘   c1, ‘銷售五部‘ c2,‘A老譚‘  c3, 1   c4 from dual union all
select ‘玉米‘   c1, ‘銷售一部‘ c2,‘老柳‘   c3, 1   c4 from dual union all
select ‘玉米‘   c1, ‘銷售一部‘ c2,‘老柳‘   c3, 1   c4 from dual union all
select ‘玉米‘   c1, ‘銷售一部‘ c2,‘老王‘   c3, 1   c4 from dual;

--寫法1:
select rn,c1,rn2,c2,rn3,c3
  
 
from(select c1,c2,c3,
              dense_rank()over(order by sm desc) rn,
              dense_rank()over(partition by c1 order by sm2 desc) rn2,
              row_number()over(partition by c1,c2 order by sm3 desc) rn3
         from(select distinct t1.c1,t1.c2,t1.c3,
                     sum(t1.c4)over(partition by t1.c1) sm,
                     sum(t1.c4)over(partition by t1.c1,t1.c2) sm2,
                     sum(t1.c4)over(partition by t1.c1,t1.c2,t1.c3) sm3
                from tmp t1
             )
       )
where rn <= 3 and rn2 <= 3 and rn3 = 1
order by rn,rn2,rn3;
 
--寫法2
select rn,c1,rn2,c2,rn3,c3
  from(select c1,c2,c3,
              dense_rank()over(order by sm desc) rn,
              dense_rank()over(partition by c1 order by sm2 desc) rn2,
              dense_rank()over(partition by c1,c2 order by sm3 desc) rn3
         from(select distinct t1.c1,t1.c2,t1.c3,
                     sum(t1.c4)over(partition by t1.c1) sm,
                     sum(t1.c4)over(partition by t1.c1,t1.c2) sm2,
                     sum(t1.c4)over(partition by t1.c1,t1.c2,t1.c3) sm3
                from tmp t1
             )
       )
where rn <= 3 and rn2 <= 3 and rn3 = 1
order by rn,rn2,rn3;

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