如何按升序选择每个类别的最高价格的行？

Posted 2023-02-16

【中文标题】如何按升序选择每个类别的最高价格的行？

【英文标题】：How to select row that have the max price of each category in asc order?

【发布时间】：2021-05-27 00:17:23

【问题描述】：

下面是我的表格，其中包含以下项目：

ProductId	ProductName	Category	Price
13	Cadbury	C-1	$12.00
21	Nestle	C-1	$13.99
73	Amul	C-101	$9.00
43	Ghirardelli	C-101	$10.88
105	Snickers	C-2	$18.90
677	Amul	C-3	$30.19
107	Kit Kat	C-2	$2.00
899	Ferrero Rocher	C-4	$5.00
209	Spy	C-3	$4.00
1014	Naviluna	C-1	$13.99
1561	Twix	C-101	$10.88

我想要的输出是：-

ProductId	ProductName	Category	Price
21	Nestle	C-1	$13.99
105	Snickers	C-2	$18.90
677	Amul	C-3	$30.19
899	Ferrero Rocher	C-4	$5.00
43	Ghirardelli	C-101	$10.88

如果最高价格相同，则按类别 asc 查找具有最高价格和最低 product_id 组的行

【问题讨论】：

。 .我删除了不一致的数据库标签。请仅使用您真正使用的数据库进行标记。

【参考方案1】：

猜测是这样的：

设置测试数据

create table prices (productid, productname, category, price) as
select   13, 'Cadbury'       , 'C-1'  , '$12.00' from dual union all
select   21, 'Nestle'        , 'C-1'  , '$13.99' from dual union all
select   73, 'Amul'          , 'C-101',  '$9.00' from dual union all
select   43, 'Ghirardelli'   , 'C-101', '$10.88' from dual union all
select  105, 'Snickers'      , 'C-2'  , '$18.90' from dual union all
select  677, 'Amul'          , 'C-3'  , '$30.19' from dual union all
select  107, 'Kit Kat'       , 'C-2'  ,  '$2.00' from dual union all
select  899, 'Ferrero Rocher', 'C-4'  ,  '$5.00' from dual union all
select  209, 'Spy'           , 'C-3'  ,  '$4.00' from dual union all
select 1014, 'Naviluna'      , 'C-1'  , '$13.99' from dual union all
select 1561, 'Twix'          , 'C-101', '$10.88' from dual
;

查询和输出

with prep as (
  select productid, productname, category, price,
         to_number(price, '$999.99') as num_price
  from   prices
)
select min(productid) keep (dense_rank first 
              order by num_price desc nulls last) as productid,
       min(productname) keep (dense_rank first
              order by num_price desc nulls last, productid) as productname,
       category,
       max(price) keep (dense_rank first 
              order by num_price desc nulls last) as price
from   prep
group  by category
order  by to_number(substr(category, instr(category, '-') + 1))
;

PRODUCTID PRODUCTNAME    CATEGORY PRICE 
--------- -------------- -------- ------
       21 Nestle         C-1      $13.99
      105 Snickers       C-2      $18.90
      677 Amul           C-3      $30.19
      899 Ferrero Rocher C-4      $5.00 
       43 Ghirardelli    C-101    $10.88

【参考方案2】：

你可以使用row_number():

select t.*
from (select t.*,
             row_number() over (partition by category order by price desc, product_id asc) as seqnum
      from t
     ) t
where seqnum = 1;

【讨论】：

嗨@Gordon Linoff，该类别是否按asc 排序？如果是这样，你能解释一下吗？

@Sunny 。 . .此答案中没有任何内容按category 排序。当然，这可以添加到外部查询中。