I can sort an array like that :

results = rs.sort_by{|p| p.km}

but I tried to add a scrond sorting criteria like that :

results = rs.sort_by{|p| p.km, p.updated_at }

and I got obviously an error ...   parse error, unexpected '}', 
expecting tCOLON2 or '[' or '.'

canot find the correct writing..

appreciate any help...

thanks

joss