Question

我有一张看起来像这样的表：

ComputerID | Free_Space | Disk_Size
------------------------------------------
Computer1  | 10         | 15
Computer1  | 10         | 10
Computer1  | 05         | 10
Computer2  | 05         | 05
Computer2  | 05         | 10
Computer3  | 11         | 15
Computer3  | 04         | 05

我需要实现这样的目标：

ComputerID | Free_Space | Disk_Size
------------------------------------------
Computer1  | 25         | 35
Computer2  | 10         | 15
Computer3  | 15         | 20

我尝试过这样的事情，但没有成功。

 SELECT ComputerID,
 SUM(free_space/1000000000) AS 'Total Free Space',
 SUM(disk_size/1000000000) AS 'Total Size'
 FROM myTable
 ORDER BY ComputerID

非常感谢任何帮助。

Answer 1

SELECT ComputerID,
SUM(free_space/1000000000) AS 'Total Free Space',
SUM(disk_size/1000000000) AS 'Total Size'
FROM myTable
GROUP BY ComputerID

Answer 2

要实现您现在提出的问题，只需执行以下操作：

SELECT ComputerID,
SUM(free_space) AS 'Total Free Space',
SUM(disk_size) AS 'Total Size'

FROM myTable

GROUP BY ComputerID

如果值以字节为单位并且您希望以gb显示它们，请执行以下操作：

SELECT ComputerID,
SUM(free_space/1073741824) AS 'Total Free Space',
SUM(disk_size/1073741824) AS 'Total Size'

FROM myTable

GROUP BY ComputerID

Answer 3

使用与非聚合字段（computerid）混合的聚合函数（例如sum（））的任何查询都必须使用group by子句：

SELECT ...
FROM ...
GROUP BY ComputerID
ORDER BY ...

Answer 4

您需要GROUP BY子句

SELECT
    ComputerID,
    SUM(free_space/1000000000) AS "Total Free Space",
    SUM(disk_size/1000000000) AS "Total Size"
FROM
    myTable
GROUP BY
    ComputerID
ORDER BY
    ComputerID

另请注意，大多数SQL方言使用单引号作为字符串分隔符，使用双引号作为列名称的分隔符。使用SQL Server，您还可以使用方括号

[Total Free Space]。

如何计算SQL上的多行

4 个答案: