postgresql - Rails joins value from association -

i have 2 model group , item

class group < activerecord::base     has_many :items end  class item < activerecord::base     belongs_to :group end

my query

group.joins(:items).select('items.created_at item_created_at, groups.*').where("items.created_at > ?", time)

i need load uniq groups field 'item_created_at' max(items.created_at)

do mean like: group.joins(:items).select('max(items.created_at), groups.*').references(:items) ?

not sure if want, think fetch groups , newest items' created_at.

Braziel