select *
FROM      data c
left join data_status s on s.id = c.status
left join comments cc2 on cc2.objectid = c.id 
                      and cc2.id = ( select com.id
                                     from comments com
                                     where com.objectid = c.id
                                     order by com.dat desc limit 1 
                                    )
ORDER BY s.name ASC LIMIT 0, 50;

SELECT d1.*,
       ds1.*
FROM      data d1
LEFT JOIN data_status ds1 ON ds1.id = d1.status
LEFT JOIN (      comments c1
            JOIN ( SELECT c2.objectid, MAX(c2.dat) dat
                   FROM comments c1
                   GROUP BY c2.objectid 
                  ) c3 ON c3.objectid = c1.objectid
          ) ON c1.objectid = d1.id