如果数据不是太大，则可以在MySQL中使用此技巧:

If your data is not too large, then you can use this trick in MySQL:

select user_id, max(dte),
       substring_index(group_concat(place_visited order by cnt desc), ',', 1)
from (select user_id, place_visited, count(*) as cnt, max(recorded_date) as dte
      from user_places
      group by user_id, place_visited
     ) upv
group by user_id;