Laravel Update Query

You could use the Laravel query builder, but this is not the best way to do it.

Check Wader's answer below for the Eloquent way - which is better as it allows you to check that there is actually a user that matches the email address, and handle the error if there isn't.

DB::table('users')
        ->where('email', $userEmail)  // find your user by their email
        ->limit(1)  // optional - to ensure only one record is updated.
        ->update(array('member_type' => $plan));  // update the record in the DB. 

If you have multiple fields to update you can simply add more values to that array at the end.

$update = \DB::table('student') ->where('id', $data['id']) ->limit(1) ->update( [ 'name' => $data['name'], 'address' => $data['address'], 'email' => $data['email'], 'contactno' => $data['contactno'] ]); 

Try doing it like this.

User::where('email', $userEmail)
       ->update([
           'member_type' => $plan
        ]);

This error would suggest that User::where('email', '=', $userEmail)->first() is returning null, rather than a problem with updating your model.

Check that you actually have a User before attempting to change properties on it, or use the firstOrFail() method.

$UpdateDetails = User::where('email', $userEmail)->first();

if (is_null($UpdateDetails)) {
    return false;
}

or using the firstOrFail() method, theres no need to check if the user is null because this throws an exception (ModelNotFoundException) when a model is not found, which you can catch using App::error() http://laravel.com/docs/4.2/errors#handling-errors

$UpdateDetails = User::where('email', $userEmail)->firstOrFail();