I have the next query in mysql to get the time difference from two rows, but I would like to implement it in postgres, but I'm getting some errors when I try to query it.

select speed,mobile,date,
timediff(@nexttime,date) as tdiff2, (@nexttime:=date) as Next
from positions
where speed=0 and mobile = 1883 and date >(now() - interval 2 hour)

I have changed the last part to: (now() - interval '2 hours') but I go on getting another error in the Timediff command.

Can anyone help me please?

Best regards.