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以下是我构建的查询，用于查找特定电影的最便宜价格以及销售它的发行商，我如何操纵它，以便所有电影与销售的发行商一起列出其各自的最高电影价格它？

/*finds the cheapest price for the movie "American Beauty" and the distributor who sells it*/
SELECT movies.title, movie_distributors.distributor_name, MIN(distributed_movie_list.unit_price) AS lowest_price 
FROM distributed_movie_list 
INNER JOIN movies ON distributed_movie_list.movie_id = movies.movie_id 
INNER JOIN movie_distributors ON movie_distributors.distributor_id = distributed_movie_list.distributor_id 
WHERE movies.title = 'American Beauty' 
AND distributed_movie_list.unit_price = 
    (SELECT MIN(unit_price) 
    FROM distributed_movie_list 
    INNER JOIN movies ON distributed_movie_list.movie_id = movies.movie_id 
    WHERE movies.title = 'American Beauty') 
GROUP BY movies.title, distributed_movie_list.distributor_id, movie_distributors.distributor_name;

下表用于此查询：

create table movies (
movie_id              number(5),
title                 varchar2(30) not null,
category_code         char(3) not null,
description           varchar2(500),
released_by           number(3) not null,
released_on           date not null
);

create table movie_distributors(
distributor_id      number(3),
distributor_name    varchar2(30) not null,
location            varchar2(40),
contact             varchar2(40)
);

create table distributed_movie_list(
distribution_id           number(8),
movie_id                  number(5) not null,
distributor_id            number(3) not null,
distribute_type           varchar2(10),
inventory_quantity        number(3) default 0,
unit_price                number(8,2)
);

我正在寻找的最终结果是列出每部电影的发行商和最高价格的查询。任何帮助将不胜感激 ; )

4

3 回答 3

2

我正在寻找的最终结果是列出每部电影的发行商和最高价格的查询

那为什么不只是GROUP BY title, distributor_name这样MAX：

SELECT 
  m.movie_id,
  m.title,
  md.distributor_name, 
  MAX(d.unit_price) AS Highest_price 
FROM distributed_movie_list   AS d
INNER JOIN movies             AS m  ON d.movie_id        = m.movie_id 
INNER JOIN movie_distributors AS md ON md.distributor_id = d.distributor_id 
GROUP BY m.movie_id,m.title,
         md.distributor_name
HAVING MAX(d.unit_price) = (SELECT MAX(d2.unit_price)
                            FROM  distributed_movie_list d2
                            WHERE m.movie_id = d2.movie_id)
于 2013-02-01T18:29:10.610 回答
1

以下应该适用于大多数 RDBMS：

SELECT DISTINCT m.title, md.distributor_name, dml.unit_price AS highest_price 
FROM distributed_movie_list dml
INNER JOIN movies m ON dml.movie_id = m.movie_id 
INNER JOIN movie_distributors md ON md.distributor_id = dml.distributor_id 
INNER JOIN (SELECT movie_id, MAX(unit_price) 
            FROM distributed_movie_list
            GROUP BY movie_id) dmlh
        ON dml.unit_price = dmlH.unit_price AND dml.movie_id = dmlh.movie_id

对于支持排名函数的 RDBMS（例如 Oracle 或 SQLServer），应该有一个更有效的解决方案。

于 2013-02-01T18:59:06.190 回答
1

如果您想获得每部电影的最高价格 - 以及相关信息 - 然后使用该row_number()功能。以下查询返回有关每部电影最高价格的所有信息：

select dml.*
from (select dml.*,
             ROW_NUMBER() over (partition by movie_id order by unit_price desc) as seqnum
      from distributed_movie_list dml 
     ) dml
where seqnum = 1

您可以加入有关电影和发行商的其他信息。

于 2013-02-01T18:59:12.747 回答