Eloquent 中的什么方法或 Laravel 5.2 中的查询生成器用于唯一值

What method in Eloquent or Query Builder in Laravel 5.2 for unique values

场景如下

Table:用户

id | name | grade ------ | ------|------ 1 | Mark | a 2 | Earl | a 3 | John | c 4 | Mike | d 5 | Matt | e

我想要做的是填充 non-repeating 或 non-duplicate 的成绩

所以它应该只显示

c
d
e


我已经走到这一步了

控制器
$grades = user::select('grade') ->distinct() ->get();

blade
@foreach ($grades as $grade) {{ $grade }}<br> @endforeach<br><br>

然而,这个查询给出了这个

一个
c
d
e

试试这个查询:-

$grades = DB::select(DB::raw('SELECT grade , count(grade) as gradecount  FROM users  group 
by grade having gradecount = 1'));

                    OR

$grades = DB::table('users')
            ->select('*', DB::raw('COUNT(grade) as gradecount'))
            ->groupBy('grade')
            ->having('gradecount', '=',1)
            ->get();

希望对您有所帮助!