Brugeraktivitetsfeed (ala facebook). Hvordan grupperer man lignende aktiviteter?

Du vil sandsynligvis gruppere på element-id'et for det element, der ændres - som i dette tilfælde ser ud som:ua.imdbID.

Når du gør det, mister du de andre rækker af data, så du vil bruge GROUP_CONCAT til at få alle relaterede id'er.

GROUP_CONCAT(sa.aktivitets-ID);

Så dit slutresultat ville være:

SELECT ua.datetime, ua.imdbID, ua.personID, GROUP_CONCAT(sa.activityID), sa.activity, m.title, m.year, p.name, umv.vote, upv.vote, r.review, t.youTubeID, ps.filename, ph.filename
FROM user_activity ua
JOIN sys_activities sa ON ua.activityID = sa.activityID
LEFT OUTER JOIN movies m ON ua.imdbID = m.imdbID
LEFT OUTER JOIN persons p ON ua.personID = p.personID
LEFT OUTER JOIN user_movies_vote umv ON umv.userID = ua.userID AND umv.imdbID = ua.imdbID
LEFT OUTER JOIN user_persons_vote upv ON upv.userID = ua.userID AND upv.personID = ua.personID
LEFT OUTER JOIN reviews r ON r.userID = ua.userID AND r.imdbID = ua.imdbID
LEFT OUTER JOIN (
        select imdbID, userID, youTubeID, max(hd) as MaxTrailerStatus
        from trailers
        group by imdbID
        ) t ON ua.imdbID = t.imdbID AND ua.userID = t.userID
LEFT OUTER JOIN (
        select imdbID, filename, max(main) as MaxPosterStatus
        from posters
        group by imdbID
        ) ps ON ua.imdbID = ps.imdbID
LEFT OUTER JOIN (
        select personID, filename, max(main) as MaxPhotosStatus
        from photos
        group by personID
        ) ph ON ua.personID = ph.personID
WHERE ua.userID = ?  GROUP BY ua.imdbID


ORDER BY ua.datetime DESC