callID userID time
1      15     xx:xx
1      16     xx:xx
2      15     xx:xx
2      16     xx:xx

userID    xtime   status
15        xx:xx    t
15        xx:xx    f
.
.
.
.
16        xx:xx    f
16        xx:xx    t
.
.
.
.

select q2.uid, q2.xtime,q3.status
from
(select uid,max(xtime) as xtime
from table2

--where xtime<time from table1!!!!!!

group by uid
) q2
left join table2  q3
on q2.uid=q3.uid and q2.xtime=q3.xtime