如何在Oracle中使用级联排序来执行SELECT？

Question

我知道如何构建一个SELECT语句，通过产品代码和子模型列表的计数给出排名前10位的条目，但是如何在排名上更深入一级？那就是列出排名前10位的排名前5的排名（按统计）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 

我要寻找的SELECT语法显示前2排子模型的前3排车型

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 

（子级型号A105和所有的子模型是使用DENSE_RANK（）的结果，至少我认为它看起来应该是这样）。

Answer 1

SQL Fiddle

我会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 

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函数分配行列。

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 

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，筛选出顶级车型和子模型。

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 

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 |