On 25 Oct, 15:18, panchettone <pan_che_ttone@non_morde.bau> wrote:
> > IIRC, the SQL standard requires that when you mix aggregate functions
> > with columns (or non-aggregate functions) you must GROUP BY all
> > non-aggregate columns or functions.
>
> could you suggest a place online where I can find tips like this one?
The Reference Manual!
http://dev.mysql.com/doc/refman/5.0/en/