myself_sql = ‘select room_id,source_id user_id,min(cast(at as datetime)) joinroom,max(cast(at as datetime)) leaveroom ‘ \
‘from `event_history` where room_id={} and source_type=1 group by source_id ORDER BY source_id desc‘.format(room)
原文：https://www.cnblogs.com/xiaojinniu425/p/10203333.html