如果不是整数或日期，如何在查询生成器中获取组中的最后一项？

Question

我正在尝试使用groupby获取最后一行，我有一些重复的jobseeker_id但是不同的call_reason，status，type_of_call等..和created_at。

id jobseeker_id  type_of_call   status  call_reason        created_at
1   2001          incoming_call  good   because of track   2017.10.1
2   2001          outgoing call  fair    they called me    2017.11.2
3   2001          outgoing call  bad     something         2017.12.3
4   2002          outgoing call  good     something        2018.11.6

所以我期望只出来

id jobseeker_id  type_of_call   status  call_reason        created_at
1   2001         outgoing call  bad      something        2017.12.3
4   2002          outgoing call  good     something        2018.11.6

Here is my query

           $jobseekers =DB::table('calllogs')
  ->select(DB::raw("max(created_at),jobseeker_id,call_reason,type_of_call"))
    ->orderBy('created_at','desc')
  ->groupBy('jobseeker_id')  
  ->wherenotnull('call_back_date')
  ->get();

上面的查询给我回复

id jobseeker_id  type_of_call   status  call_reason        created_at
3   2001          incoming_call  good     because of track         2017.12.3
4   2002          outgoing call  good     something        2018.11.6

我只能获得最新的created_at日期，但我不会得到最新的staus，type_of_call，call_reason。任何人都有想法？请帮帮我。

Answer 1

不熟悉laravel但你的问题是你需要识别带有id的行，然后从中选择列。您正在尝试获取max created_at，然后只获取其余列的分组值。查询看起来像..

SELECT * FROM calllogs WHERE id IN (
(SELECT MAX(ID) FROM calllogs GROUP BY jobseeker_id);

我假设您显示的预期结果中的id应该是3而不是1.查询应该至少对我能看到的有限集合起作用。可能需要根据其余数据添加更多优化，但这可以让您了解可能有用的内容。希望这可以帮助。

Answer 2

$jobseekers =DB::table('calllogs')
  ->select(DB::raw("max(created_at),jobseeker_id,call_reason,type_of_call"))
  ->orderBy('jobseeker_id','desc')
  ->wherenotnull('call_back_date')
  ->take(2)
  ->get();