select t1.contest_id, t1.hacker_id,t1.name, t2.ts, t2.tas, t1.tv,t1.tuv from 
(select con.contest_id, con.hacker_id, con.name, sum(total_views) as tv, sum(total_unique_views) as tuv
from 
    view_stats as vs, challenges as chal, colleges as col, contests as con
    where 
    vs.challenge_id = chal.challenge_id and
    chal.college_id = col.college_id and
    col.contest_id = con.contest_id
group by con.contest_id, con.hacker_id, con.name
order by contest_id) as t1, 
(
    select con.contest_id, con.name, sum(total_submissions) as ts, sum(total_accepted_submissions) as tas 
from 
    submission_stats as ss, challenges as chal, colleges as col, contests as con
    where
    ss.challenge_id = chal.challenge_id and 
    chal.college_id = col.college_id and 
    col.contest_id = con.contest_id
group by con.contest_id, con.name
order by contest_id) as t2
where t1.contest_id = t2.contest_id