SQL: how to get a weighted count using GROUP BY?

Question

How can I make a query like:

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

But where freq sums values from a weight column instead of counting each row as 1?

I'm using MySQL 5.1.

Answer 1

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

Answer 2

You want to use the Sum aggregate function to handle this.

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

Should do the trick!

Answer 3

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

Answer 4

use sum(weight) as freq in your select query