4

我有一个类似这样的查询

SELECT 
t.category, 
tc.product, 
tc.sub-product,
 count(*) as sales 
 FROM tg t, ttc tc
 WHERE t.value = tc.value
 GROUP BY t.category, tc.product, tc.sub-product;

现在在我的查询中，我想获得每个类别的前 10 个产品（按销售额排名第一），对于每个类别，我需要前 5 个子类别（按销售额排名）

您可以假设问题陈述是这样的：

获得每个类别销售额前 10 名的产品，每个产品获得销售额前 5 名的子产品。

  • 这里的类别可以是书籍
  • 产品可以是哈利波特的书
  • 子产品可以是HarryPorter series 5

样本输入数据格式

category |product |subproduct |Sales [count (*)]

abc   test1    test11     120

abc   test1    test11     100

abc   test1    test11     10

abc   test1    test11     10

abc   test1    test11     10

abc   test1    test11     10

abc   test1    test12     10

abc   test1    test13     8

abc   test1    test14     6

abc   test1    test15     5

abc   test2    test21     80

abc   test2    test22     60

abc   test3    test31     50

abc   test3    test32     40

abc   test4    test41     30

abc   test4    test42     20

abc   test5    test51     10

abc   test5    test52     5 

abc   test6    test61     5 

|

|

|

bcd   test2    test22     10 

xyz   test3    test31     5 

xyz   test3    test32     3 

xyz   test4    test41     2

输出将是“

top 5 rf for (abc) -> abc,test1(289) abc,test2 (140), abc test3 (90), abc test4(50) , abc test5 (15)

top 5 rfm for (abc,test1) -> test11(260),test12(10),test13(8),test14(6),test15(5) and so on

我的查询失败了，因为结果非常巨大。我正在阅读有关排名等 Oracle 分析函数的信息。有人可以帮助我使用分析函数修改此查询。任何其他方法也可以工作。

我指的是这个http://www.orafaq.com/node/55。但无法为此获得正确的 sql 查询。

任何帮助将不胜感激..我在这方面被困了 2 天:(

4

2 回答 2

1

可能有理由不使用分析函数，而是单独使用分析函数：

select am, rf, rfm, rownum_rf2, rownum_rfm
from
(
    -- the 3nd level takes the subproduct ranks, and for each equally ranked
    -- subproduct, it produces the product ranking
    select am, rf, rfm, rownum_rfm,
      row_number() over (partition by rownum_rfm order by rownum_rf) rownum_rf2
    from
    (
        -- the 2nd level ranks (without ties) the products within
        -- categories, and subproducts within products simultaneosly
        select am, rf, rfm,
          row_number() over (partition by am order by count_rf desc) rownum_rf,
          row_number() over (partition by am, rf order by count_rfm desc) rownum_rfm
        from
        (
            -- inner most query counts the records by subproduct
            -- using regular group-by. at the same time, it uses
            -- the analytical sum() over to get the counts by product
            select tg.am, ttc.rf, ttc.rfm,
              count(*) count_rfm,
              sum(count(*)) over (partition by tg.am, ttc.rf) count_rf
            from tg inner join ttc on tg.value = ttc.value
            group by tg.am, ttc.rf, ttc.rfm
        ) X
    ) Y
    -- at level 3, we drop all but the top 5 subproducts per product
    where rownum_rfm <= 5   -- top  5 subproducts
) Z
-- the filter on the final query retains only the top 10 products
where rownum_rf2 <= 10  -- top 10 products
order by am, rownum_rf2, rownum_rfm;

我使用 rownum 而不是 rank 所以你永远不会得到平局，或者换句话说，平局将是随机决定的。如果数据不够密集（前 10 名产品中的任何一个少于 5 个子产品 - 它可能会显示来自其他一些产品的子产品），这也不起作用。但是如果数据密集（大型已建立的数据库），查询应该可以正常工作。

下面对数据进行了两次传递，但在每种情况下都返回正确的结果。同样，这是一个无关联的排名查询。

select am, rf, rfm, count_rf, count_rfm, rownum_rf, rownum_rfm
from
(
    -- next join the top 10 products to the data again to get
    -- the subproduct counts
    select tg.am, tg.rf, ttc.rfm, tg.count_rf, tg.rownum_rf, count(*) count_rfm,
        ROW_NUMBER() over (partition by tg.am, tg.rf order by 1 desc) rownum_rfm
    from (
        -- first rank all the products
        select tg.am, tg.value, ttc.rf, count(*) count_rf,
            ROW_NUMBER() over (order by 1 desc) rownum_rf
        from tg
        inner join ttc on tg.value = ttc.value
        group by tg.am, tg.value, ttc.rf
        order by count_rf desc
        ) tg
    inner join ttc on tg.value = ttc.value and tg.rf = ttc.rf
    -- filter the inner query for the top 10 products only
    where rownum_rf <= 10
    group by tg.am, tg.rf, ttc.rfm, tg.count_rf, tg.rownum_rf
) X
-- filter where the subproduct rank is in top 5
where rownum_rfm <= 5
order by am, rownum_rf, rownum_rfm;

列：

count_rf : count of sales by product
count_rfm : count of sales by subproduct
rownum_rf : product rank within category (rownumber - without ties)
rownum_rfm : subproduct rank within product (without ties)
于 2011-02-11T09:30:05.883 回答
0

这是猜测，但您可能可以从以下内容开始：

drop table category_sales;

一些测试数据：

create table category_sales (
   category    varchar2(14),
   product     varchar2(14),
   subproduct  varchar2(14),
   sales       number
);

begin

  for cate in 1 .. 10 loop
  for prod in 1 .. 20 loop
  for subp in 1 .. 30 loop

      insert into category_sales values (
             'Cat '  || cate,
             'Prod ' || cate||prod,
             'Subp ' || cate||prod||subp,
              trunc(dbms_random.value(1,30 + cate - prod + subp))
      );

  end loop; end loop; end loop;

end;
/

实际查询： 

select * from (
  select 
    category,
    product,
    subproduct,
    sales,
    category_sales,
    product_sales,
    top_subproduct,
    -- Finding best products within category:
    dense_rank () over (
      partition by category
      order     by product_sales desc
    ) top_product 
  from (
    select 
      -- Finding the best Subproducts within
      -- category and product:
      dense_rank () over (
         partition by category, 
                      product 
         order     by sales desc
      )                             top_subproduct,
      -- Finding the sum(sales) within a 
      -- category and prodcut
      sum(sales) over (
         partition by category, 
                      product
      )                             product_sales,
      -- Finding the sum(sales) within 
      -- category
      sum(sales) over (
         partition by category
      )                             category_sales,
      category,
      product,
      subproduct,
      sales
    from
      category_sales
  )
)
where 
--    Only best 10 Products
      top_product       <= 10 and
--    Only best 5 subproducts:
      top_subproduct    <= 5
-- "Best" categories first:
order by 
      category_sales desc,
      top_product    desc,
      top_subproduct desc;

在该查询中，该列category_sales返回其记录所在类别的销售额总和。这意味着，同一类别的每条记录都具有相同的category_sales. 需要此列来对具有最佳（销售）类别的结果集进行排序（order by ... category_sales desc）。

同样，product_sales是类别-产品组合的销售额总和。此列用于查找每个类别 ( ) 中最好的n (这里：10)where top_product <= 10产品。

该列是使用分析功能top_product“创建”的。dense_rank() over...对于一个类别中最好的产品，它是 1，对于第二好的它是 2，依此类推（因此where top_product <= 10.

该列top_suproduct的计算方式与top_product（即使用dense_rank）类似。

于 2011-02-11T09:32:31.780 回答