选择最高行

Question

请帮助我提供以下数据。应该怎么查询呢

Name        Speed Tier     Usage
Andrew         200          5000
Andrew         100          2000
Luis           100          1000

我需要以显示使用率最高的名称的方式进行查询。下面是例子

Name        Speed Tier     Usage
Andrew         200          5000
Luis           100          1000

Answer 1

SELECT TOP 1 Name
    ,Usage
FROM your TABLE
ORDER BY Usage DESC -- if you want the highest

SELECT TOP X Name
    ,Usage
FROM your TABLE
ORDER BY Usage DESC -- if you want to select the top X rows

SELECT Name
    ,MAX(Usage) Usage 
FROM your TABLE
GROUP BY Name -- if you want to know each Name's highest usage

Answer 2

我会通过 MAX 和 GROUP:

SELECT Name, Max(Usage)
FROM YourTableName
GROUP BY Name

Answer 3

我会结合使用 MAX 和 GROUP BY

SELECT Name, Max([Speed Tier]), Max(Usage)
FROM TableName
GROUP BY Name
ORDER BY Name

或者如果你只想要一个价值最高的人

SELECT TOP 1 Name, [Speed Tier], Usage
FROM TableName
GROUP BY Name
ORDER BY [Usage] desc

或者如果您想要最高的使用率以及当前行的速度

;with CTE as (SELECT TOP 1 Name, Max(Usage) as Usage
FROM @mytable
GROUP BY Name
Order by Usage desc
)
select 
    T.name, T.[Speed Tier], T.usage
from cte as C
inner join @mytable as T on T.Name = C.name and T.usage = C.Usage

Answer 4

使用相关子查询：

select t.*
from t
where t.usage = (select max(t2.usage) from t t2 where t2.name = t.name);

选择最高行

Selecting Highest rows

sql

ssrs-2012