sql - Access - Selecting unique rows with newest date -

i have access database table track assignments between laptops , vehicles called records, shows computername, unitnumber it's assigned to, , date assignment recorded.

id  computername    unitnumber  daterecorded 1   lt150           5010        8/1/2015 2   lt150           788         8/30/2015 3   lt235           4009        8/4/2015 4   lt150           123         9/21/2015 

now i'm trying find way query results show unique computername recent daterecorded.

so results be

computername    unitnumber  daterecorded lt150           123         9/21/2015 lt235           4009        8/4/2015 

i can't figure out how make query work. tried, gives me aggregate function error.

select      computername, max(daterecorded) recetdate,     unitnumber       records  group      computername  

you don't use group by type of query.

instead:

select r.* records r r.daterecorded = (select max(r2.daterecorded)                         records r2                         r2.computername = r.computername                        ); 

note: assumes same date not used twice same computer.