Question

我有以下声明：

SELECT  
    IMPORTID,Region,RefObligor,SUM(NOTIONAL) AS SUM_NOTIONAL
From 
    Positions
Where
    ID = :importID
GROUP BY 
    IMPORTID, Region,RefObligor
Order BY 
    IMPORTID, Region,RefObligor

表Positions中存在一些额外的列，我想作为“显示数据”的输出，但我不希望在group by语句中。

这些是Site, Desk

最终输出将包含以下列：

IMPORTID,Region,Site,Desk,RefObligor,SUM(NOTIONAL) AS SUM_NOTIONAL

理想情况下，我希望数据排序如下：

Order BY 
    IMPORTID,Region,Site,Desk,RefObligor

如何实现这一目标？

Answer 1

包含不属于GROUP BY子句的列是没有意义的。考虑一下SELECT子句中是否有MIN（X），MAX（Y），其他列（未分组）应该来自哪一行？

如果您的Oracle版本足够新，您可以使用SUM - OVER（）来显示针对每个数据行的SUM（分组）。

SELECT  
    IMPORTID,Site,Desk,Region,RefObligor,
    SUM(NOTIONAL) OVER(PARTITION BY IMPORTID, Region,RefObligor) AS SUM_NOTIONAL
From 
    Positions
Where
    ID = :importID
Order BY 
    IMPORTID,Region,Site,Desk,RefObligor

或者，您需要从Site，Desk列中进行汇总

SELECT  
    IMPORTID,Region,Min(Site) Site, Min(Desk) Desk,RefObligor,SUM(NOTIONAL) AS SUM_NOTIONAL
From 
    Positions
Where
    ID = :importID
GROUP BY 
    IMPORTID, Region,RefObligor
Order BY 
    IMPORTID, Region,Min(Site),Min(Desk),RefObligor

Answer 2

我相信这是

select
  IMPORTID,
  Region,
  Site,
  Desk,
  RefObligor,
  Sum(Sum(Notional)) over (partition by IMPORTID, Region, RefObligor) 
from
  Positions
group by
  IMPORTID, Region, Site, Desk, RefObligor
order by
  IMPORTID, Region, RefObligor, Site, Desk;

......但如果没有进一步的信息和/或测试数据，很难说清楚。

Answer 3

一篇很好的博客文章详细介绍了这个困境：

http://bernardoamc.github.io/sql/2015/05/04/group-by-non-aggregate-columns/

以下是它的一些片段：

假设：

CREATE TABLE games (
  game_id serial PRIMARY KEY,
  name VARCHAR,
  price BIGINT,
  released_at DATE,
  publisher TEXT
);

INSERT INTO games (name, price, released_at, publisher) VALUES
  ('Metal Slug Defense', 30, '2015-05-01', 'SNK Playmore'),
  ('Project Druid', 20, '2015-05-01', 'shortcircuit'),
  ('Chroma Squad', 40, '2015-04-30', 'Behold Studios'),
  ('Soul Locus', 30, '2015-04-30', 'Fat Loot Games'),
  ('Subterrain', 40, '2015-04-30', 'Pixellore');

SELECT * FROM games;

 game_id |        name        | price | released_at |   publisher
---------+--------------------+-------+-------------+----------------
       1 | Metal Slug Defense |    30 | 2015-05-01  | SNK Playmore
       2 | Project Druid      |    20 | 2015-05-01  | shortcircuit
       3 | Chroma Squad       |    40 | 2015-04-30  | Behold Studios
       4 | Soul Locus         |    30 | 2015-04-30  | Fat Loot Games
       5 | Subterrain         |    40 | 2015-04-30  | Pixellore
(5 rows)

试图得到这样的东西：

SELECT released_at, name, publisher, MAX(price) as most_expensive
FROM games
GROUP BY released_at;

但由于汇总时含糊不清，因此未添加name和publisher ...

让我们说清楚：
Selecting the MAX(price) does not select the entire row.
数据库无法知道，何时无法给出正确答案   给定查询的时间应该给我们一个错误，那就是它   确实！

好的......好的......这不是那么简单，我们能做些什么？

使用inner join获取其他列

SELECT g1.name, g1.publisher, g1.price, g1.released_at
FROM games AS g1
INNER JOIN (
  SELECT released_at, MAX(price) as price
  FROM games
  GROUP BY released_at
) AS g2
ON g2.released_at = g1.released_at AND g2.price = g1.price;

或者使用left outer join获取其他列，然后按重复列的NULL进行过滤...

SELECT g1.name, g1.publisher, g1.price, g2.price, g1.released_at
FROM games AS g1
LEFT OUTER JOIN games AS g2
ON g1.released_at = g2.released_at AND g1.price < g2.price
WHERE g2.price IS NULL;

希望有所帮助。

如何选择和排序不在Group By SQL语句中的列 - Oracle

3 个答案: