Question

我知道如何构建一个SELECT语句，按照产品代码和子模型列表的数量给出排名前10位的条目，但是如何在排名上更深入一级？那就是列出前10名排名模型中排名前5位（按计数）的子模型？

例如：

CREATE TABLE RANKTEST ( 
"MODEL"    VARCHAR2(5 BYTE),  
"SUBMODEL" VARCHAR2(5 BYTE)  ) ; 

insert into ranktest values('A100','R1');
insert into ranktest values('A100','R1');
insert into ranktest values('A100','R1');
insert into ranktest values('A100','R1');
insert into ranktest values('A100','R2');
insert into ranktest values('A100','R2');
insert into ranktest values('A100','R3');
insert into ranktest values('A100','R4');
insert into ranktest values('A103','R5');
insert into ranktest values('A103','R5');
insert into ranktest values('A103','R5');
insert into ranktest values('A103','R5');
insert into ranktest values('A103','X1');
insert into ranktest values('A103','X1');
insert into ranktest values('A103','X1');
insert into ranktest values('A103','X2');
insert into ranktest values('A103','X2');
insert into ranktest values('A103','X3');
insert into ranktest values('A104','R1');
insert into ranktest values('A104','R2');
insert into ranktest values('A105','R2');
insert into ranktest values('A105','R3');
insert into ranktest values('A105','R4');
commit;


SELECT model,
   cnt,
   rank
FROM
  (SELECT model,
     COUNT(*)  AS cnt,
     DENSE_RANK() OVER(ORDER BY COUNT(model) DESC) AS rank
  FROM
  ( SELECT * FROM ranktest )
  GROUP BY model )
  WHERE rank <=3;

  This gives the result:

MODEL  CNT    RANK
A103   10      1
A100    8      2
A105    3      3

我正在寻找SELECT语法来显示排名前3位的模型排名前2位的子模型

MODEL SUBMODEL CNT RANK SUB-COUNT SUB-RANK
A103    R5      10   1      4        1  
A103    X1      10   1      3        2
A100    R1       8   2      4        1
A100    R2       8   2      2        2
A105    R2       3   3      1        1
A105    R3       3   3      1        1
A105    R4       3   3      1        1

（模型A105及其所有子模型的子排名是使用DENSE_RANK（）的结果，至少我认为它应该看起来。）

Answer 1

SQL Fiddle

我首先计算模型和子模型的数量。

查询1 ：

select model_, submodel_, 
       count(*) submodel_count,
       sum(count(*)) over (partition by model_) model_count
from ranktest
group by model_, submodel_
order by 1,2,3 desc

<强> Results ：

| MODEL_ | SUBMODEL_ | SUBMODEL_COUNT | MODEL_COUNT |
|--------|-----------|----------------|-------------|
|   A100 |        R1 |              4 |           8 |
|   A100 |        R2 |              2 |           8 |
|   A100 |        R3 |              1 |           8 |
|   A100 |        R4 |              1 |           8 |
|   A103 |        R5 |              4 |          10 |
|   A103 |        X1 |              3 |          10 |
|   A103 |        X2 |              2 |          10 |
|   A103 |        X3 |              1 |          10 |
|   A104 |        R1 |              1 |           2 |
|   A104 |        R2 |              1 |           2 |
|   A105 |        R2 |              1 |           3 |
|   A105 |        R3 |              1 |           3 |
|   A105 |        R4 |              1 |           3 |

然后使用dense_rank函数指定排名。

查询2 ：

select model_, submodel_, model_count, submodel_count, 
       dense_rank() over (order by model_count desc) model_rank,
       dense_rank() over (partition by model_ order by submodel_count desc) submodel_rank
from (
select model_, submodel_, 
       count(*) submodel_count,
       sum(count(*)) over (partition by model_) model_count
from ranktest
group by model_, submodel_
)
order by 1,2,5,6

<强> Results ：

| MODEL_ | SUBMODEL_ | MODEL_COUNT | SUBMODEL_COUNT | MODEL_RANK | SUBMODEL_RANK |
|--------|-----------|-------------|----------------|------------|---------------|
|   A100 |        R1 |           8 |              4 |          2 |             1 |
|   A100 |        R2 |           8 |              2 |          2 |             2 |
|   A100 |        R3 |           8 |              1 |          2 |             3 |
|   A100 |        R4 |           8 |              1 |          2 |             3 |
|   A103 |        R5 |          10 |              4 |          1 |             1 |
|   A103 |        X1 |          10 |              3 |          1 |             2 |
|   A103 |        X2 |          10 |              2 |          1 |             3 |
|   A103 |        X3 |          10 |              1 |          1 |             4 |
|   A104 |        R1 |           2 |              1 |          4 |             1 |
|   A104 |        R2 |           2 |              1 |          4 |             1 |
|   A105 |        R2 |           3 |              1 |          3 |             1 |
|   A105 |        R3 |           3 |              1 |          3 |             1 |
|   A105 |        R4 |           3 |              1 |          3 |             1 |

最后，过滤掉顶级模型和子模型。

查询3 ：

select model_, submodel_, model_count, submodel_count,
       model_rank, submodel_rank
from (
select model_, submodel_, model_count, submodel_count, 
       dense_rank() over (order by model_count desc) model_rank,
       dense_rank() over (partition by model_ order by submodel_count desc) submodel_rank
from (
select model_, submodel_, 
       count(*) submodel_count,
       sum(count(*)) over (partition by model_) model_count
from ranktest
group by model_, submodel_
)
)
where model_rank <=3 and submodel_rank <=2

<强> Results ：

| MODEL_ | SUBMODEL_ | MODEL_COUNT | SUBMODEL_COUNT | MODEL_RANK | SUBMODEL_RANK |
|--------|-----------|-------------|----------------|------------|---------------|
|   A103 |        R5 |          10 |              4 |          1 |             1 |
|   A103 |        X1 |          10 |              3 |          1 |             2 |
|   A100 |        R1 |           8 |              4 |          2 |             1 |
|   A100 |        R2 |           8 |              2 |          2 |             2 |
|   A105 |        R2 |           3 |              1 |          3 |             1 |
|   A105 |        R4 |           3 |              1 |          3 |             1 |
|   A105 |        R3 |           3 |              1 |          3 |             1 |

如何在Oracle中使用级联排名进行SELECT？

1 个答案: