在mysql中选择不同的对，并选择第三个值的总和

Question

I'm trying to achieve the following: In a table with three values, for each distinct combination of values in two columns, I wan't to sum the values in the third column.

Eg.

The following table:

mysql> select * from test; +------+------+------+ | A | B | num | +------+------+------+ | e | f | 34 | | e | f | 45 | | g | h | 22 | | a | f | 55 | | d | g | 66 | | e | f | 67 | | a | f | 88 | | e | g | 36 | | d | g | 44 | +------+------+------+

I would like:

+------+------+ | A | B | +------+------+ | e | f | 146 | g | h | 22 | a | f | 143 | d | g | 110 | e | g | 36 +------+------+

I initially thought this would be a simple combination of DISTINCT and SUM(), but no - can't seem to make any progress. Combining it with a subquery also proved difficult. Various similar, but not identical questions have been asked. But not quite the same, and the solutions did not work.

Can anyone help me with this seemingly simple question?

Answer 1

使用group by 。

select A,B, sum(num) from test group by A,B;

Answer 2

随身携带：

select sum(num),col1,col2 from table group by col1,col2

Answer 3

Try this query --

SELECT A
    ,B
    ,Sum(Number) AS Total
FROM TableName
GROUP BY A, B
ORDER BY A, B;