怎么去重并保留时间最晚也就是最大的值

Question

$events = $events->select('y_people_lib_id','location_id')->whereIn('location_id',$Inlocation)->where('created_at','>=',$date.' '.'00:00:01')->where('created_at','<=',$date.' '.'23:59:59')->orderBy('created_at', 'DESC')->groupBy('y_people_lib_id')->get()->toArray();
这是我现在写的 我想y_people_lib_id去重 并保留created_at最大的值

Answer 1

我能想到的是子查询，类似下面这样子，select * from (SELECT * FROM location_exception ORDER BY date_time DESC) as b group by device_id;