如何使用Laravel 4的Eloquent ORM从数据库中选择一个随机条目？

Question

I have an Eloquent model called Question linked to a database table named questions.

Is there an Eloquent function that will let me take a single random question (or a set number of random questions) from the database? Something like the following:

$random_question = Question::takeRandom(1)->get();

or

$random_questions = Question::takeRandom(5)->get();

Answer 1

Simply you can do:

$random_question = Question::orderBy(DB::raw('RAND()'))->take(1)->get();

and

$random_question = Question::orderBy(DB::raw('RAND()'))->take(5)->get();

If you want to use the syntax as you specified in your question, you can use scopes. In the model Question you can add the following method:

public function scopeTakeRandom($query, $size=1)
{
    return $query->orderBy(DB::raw('RAND()'))->take($size);
}

Now you can do $random_question = Question::takeRandom(1)->get(); and get 1 random question.

You can read more about Laravel 4 query scopes at http://laravel.com/docs/eloquent#query-scopes