zkuste toto :-
select t1.user, t1.date d1,t2.date d2 ,t1.date-t2.date
from (select @val:[email protected]+1 rowid,user, date
from mytable,(select @val:=0) a
order by user,date) t1,
(select @val1:[email protected]+1 rowid,user, date
from mytable,(select @val1:=1) b
order by user,date) t2
where t1.rowid = t2.rowid
and t1.user = t2.user
and t1.date-t2.date < 1300;
viz DEMO