>When there is no ORDER BY clause, the GROUP BY clause seems to cause the records to be
>returned ordered by the group column.
>
>I don't see this in the docs. Is this the correct behaviour?

When there's no ORDER BY clause the order of the records returned is not guarantied. Using the GROUP BY can result in the records be ordered by columns listed in the GROUP BY but it's not a standard behavior and you should not not rely on it.