这是一个简单的代码来检查电子邮件是否存在数据库

    $data = $request->all();
    $user = DB::table('User')->pluck('email')->toArray();
    if(in_array($user,$data['email']))
    {
    echo 'existed email';
    }

if ($u = User::where('email', '=', $value)->first())
{
   // do something with $u
   return 'exists';
} else {
  return 'nope';
}

可以用try/catch吗

->get()仍然返回一个空数组

这将检查表中是否存在特定的电子邮件地址:

if (isset(User::where('email', Input::get('email'))->value('email')))
{
    // Input::get('email') exist in the table 
}

我解决了这个问题，使用empty()函数:

$user = User::where('email', Input::get('email'))->get()->first();
//for example:
if (!empty($user))
    User::destroy($user->id);

$email = User::find($request->email);
If($email->count()>0)
<h1>Email exist, please make new email address</h1>
endif

$user = User::where('email', request('email'))->first();
return (count($user) > 0 ? 'Email Exist' : 'Email Not Exist');