After having searched around quite a bit for a solution, I shall resort to asking the question myself. (Having already read numerous forum posts, this article (Debunking GROUP BY Myths) [dev.mysql.com] and the MySQL manual on aggregate functions [dev.mysql.com].)

Apologies if I've omitted some info, this is my first time posting to such a forum.

I've got a table of 'offers', where I'm trying to find the best (cheapest) offer for each source, so I initially thought of a query along the lines of :

SELECT id, url, source, MIN(price) FROM offers GROUP BY source

The problem I have is that the GROUP BY returns the first corresponding ID for that source, rather than the corresponding ID & URL for the minimum price that is returned. I tried adding ORDER BY price to the end of the query, but it does the ordering post-grouping...

Any help would be gratefully received!

To give you an idea of the data, in it's simplified form:

id ¦ url ¦ source ¦ price
--------------------------------
1 ¦ ... ¦ 1 ¦ 455
2 ¦ ... ¦ 3 ¦ 10
3 ¦ ... ¦ 2 ¦ 103
4 ¦ ... ¦ 2 ¦ 399
5 ¦ ... ¦ 3 ¦ 254
6 ¦ ... ¦ 1 ¦ 178
7 ¦ ... ¦ 1 ¦ 89

...and the data I'd like out is :

id ¦ url ¦ source ¦ price
--------------------------------
2 ¦ ... ¦ 3 ¦ 10
3 ¦ ... ¦ 2 ¦ 103
7 ¦ ... ¦ 1 ¦ 89

Thank you.