如何根据一列的最大值选择表中不同的数据？

Question

我有如下表：

A  B   C  D   E  F 
James Michael 123  Hello  World 1 
James Michael 123  Hello  World 5 
James Michael 123  Hello  World 7 
Harold Reynolds 345  There  Poop  1 
John  Lowland 555  Woh  Pop  1 
Howard Yow  255  Man  That  1 

我希望能够基于F的MAX值来选择所有行

的结果应该是：

James Michael 123  Hello  World 
Harold Reynolds 345  There  Poop  
John  Lowland 555  Woh  Pop  
Howard Yow  255  Man  That  

Answer 1

你可以用ROW_NUMBER()功能做到这一点：

;with cte AS (SELECT *,ROW_NUMBER() OVER(PARTITION BY "C" ORDER BY "F" DESC) AS RN 
       FROM Table1) 
SELECT "A", "B", "C", "D", "E" 
FROM cte 
WHERE RN = 1 

Demo ：SQL Fiddle

的ROW_NUMBER()函数生成一个数从1开始对各组中的PARTITION BY条款（可选）利用字段的每行和顺序由ORDER BY条款（必需）确定。

注意：我假设您的C字段足以识别一行，但如果不是这种情况，您可能需要将字段添加到PARTITION BY子句。

Answer 2

我们可以使用ROW_NUMBER，结果分区和从分区

Select * from 
    (select *, row_number() over ( partition by A, B, C,D ,E order by F desc) as seq from tableA) T 
    Where T.seq =1 

Answer 3

只得到1行由于这是第DISTINCT ON是正确的做法：

SELECT * FROM(
    SELECT DISTINCT ON ("A","B","C","D","E") "A","B","C","D","E","F" 
FROM table1 
ORDER BY "A","B","C","D","E","F" DESC) AS q 
ORDER BY "F" DESC; 

外部查询是否有刚把詹姆斯放在首位。

fiddle