Question

I have a table like this one:

id	group	value
1	GROUP A	0.641028
2	GROUP B	0.946927
3	GROUP A	0.811552
4	GROUP C	0.216978
5	GROUP A	0.650232

If I perform the following query:

SELECT `id`, SUM(`value`) AS `sum` FROM `test` GROUP BY `group`;

I, obviously, get:

id	sum
1	2.10281205177307
2	0.946927309036255
4	0.216977506875992

But I need a table like this one:

id	sum
1	2.10281205177307
2	0.946927309036255
3	2.10281205177307
4	0.216977506875992
5	2.10281205177307

Where summed rows are explicitly repeated.

Is there a way to obtain this result without using multiple (nested) queries?

Answer 1

IT would depend on your SQL server, in Postgres/Oracle I’d use Window Functions. In MySQL… not possible afaik.

Perhaps you can fake it like this:

SELECT a.id, SUM(b.value) AS `sum`
FROM test AS a
JOIN test AS b ON a.`group` = b.`group`
GROUP BY a.id, b.`group`;