SELECT
    CONTESTS.CONTEST_ID,
    CONTESTS.HACKER_ID,
    CONTESTS.NAME,
    SUM(SUBMISSION_STATS.TOTAL_SUBMISSIONS) AS S1,
    SUM(SUBMISSION_STATS.TOTAL_ACCEPTED_SUBMISSIONS) AS S2,
    SUM(VIEW_STATS.TOTAL_VIEWS) AS S3,
    SUM(VIEW_STATS.TOTAL_UNIQUE_VIEWS) AS S4
FROM CONTESTS
LEFT JOIN COLLEGES
ON CONTESTS.CONTEST_ID = COLLEGES.CONTEST_ID
LEFT JOIN CHALLENGES 
ON CHALLENGES.COLLEGE_ID = COLLEGES.COLLEGE_ID
LEFT JOIN SUBMISSION_STATS
ON SUBMISSION_STATS.CHALLENGE_ID = CHALLENGES.CHALLENGE_ID
LEFT JOIN VIEW_STATS
ON VIEW_STATS.CHALLENGE_ID = CHALLENGES.CHALLENGE_ID
GROUP BY 1,2,3
HAVING NOT S1=0 OR NOT S2=0