使用特定ID计算MySQL中的值

Question

好的,这应该很简单:

ID | version | downloads
========================
 1 |   1.0   |     2
 1 |   1.1   |     4
 1 |   1.2   |     7
 1 |   1.3   |     3
 2 |   1.0   |     3
 2 |   2.0   |     3
 2 |   3.0   |    13

无论哪个版本,我都希望获得特定产品(ID)的下载.这不起作用

SELECT COUNT(*) AS downloads FROM table WHERE ID = 1

应该返回2 + 4 + 7 + 3 = 16

Answer 1

您的输出表明您要对下载列求和.所以你必须使用sum aggregate函数..

   SELECT Sum(downloads) AS downloads FROM table WHERE ID = 1

如果您想要每个ID的总和(下载),只需更改查询,如下所示

 SELECT ID,Sum(downloads) AS downloads FROM table group by ID

如果您需要总记录数,则只使用Count

SELECT Count(*) AS count FROM table WHERE ID = 1