Mysql ve为1（单身人数）。请原谅我的错误解释。@Komal按名称分组没有帮助，因为firstname和lastname也在同一字段中。我认为他需要把姓和名分开。 | id | person_id | name | +----+-------

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ve为1（单身人数）。请原谅我的错误解释。@Komal按名称分组没有帮助，因为firstname和lastname也在同一字段中。我认为他需要把姓和名分开。

| id | person_id    | name       | 
+----+--------------+------------|        
|  1 | NULL         | John Doe   |
+----+--------------+------------|    
|  2 | NULL         | Jane Doe   |  
+----+--------------+------------+ 
|  3 | 1            | Junior J.D.|  
+----+--------------+------------+
|  4 | 1            | Senior J.D.|  
+----+--------------+------------+

 $query = DB::table('people')
                 ->select(DB::raw('count(*) as count'))
                 ->where('person_id', '=', NULL)
                 ->get();

$query = DB::table('people')
             ->whereNull('person_id')
             ->whereIn('id', function($query) {
                 $query->select('person_id')
                       ->from('people')
                       ->whereNotNull('person_id');
             }, 'and', TRUE)
             ->count();

$query = DB::table('people')
        ->whereNull('person_id')
        ->groupBy('name')
        ->count();

$query = DB::table('people')
    ->whereNull('person_id')
    ->groupBy('lastname')
    ->count();