sql - SQL：如何使用 GROUP BY 获得加权计数？

Question

如何进行如下查询：

select myvalue, count() as freq from mytable group by myvalue;

但是在哪里对列中的freq值求和weight而不是将每一行都计为 1？

我正在使用 MySQL 5.1。

score 3 · Accepted Answer

您想使用Sum聚合函数来处理此问题。

SELECT MyValue, Sum(weight) AS Total
FROM mytable
GROUP BY myvalue;

应该做的伎俩！

score 2 · Accepted Answer

2

select myvalue, sum(weight) as freq from mytable group by myvalue;

于 2010-09-29T16:41:40.083 回答

score 2 · Accepted Answer

2

select myvalue, SUM(weight) as freq from mytable group by myvalue;

于 2010-09-29T16:41:51.550 回答

score 1 · Accepted Answer

1

sum(weight) as freq在您的选择查询中使用

于 2010-09-29T16:42:31.253 回答

4 回答 4