"Gaetano Mendola" <mendola@bigfoot.com> wrote in message
news:alq3mr$2s7o$1@news.hub.org...
> Hi all,
>
> Suppose that I have a table like this:
>
>
> att_1 | att_2 | att_3 | att_4
> --------------------------------
> 1 | a | y | y1
> 2 | b | y | y2
> 3 | a | xx | y3
> 4 | c | zz | y4
> 5 | a | t | y5
> 6 | c | x | y6
>
>
>
> I want obtain all row that have for each att_2
> the max of att_1
I forgot to say: "with a single total query without sub select "
Ciao
Gaetano