Laravel 4中的雄辩调用：在多个表上处理单个列

I'm back with another Laravel issue that I can't seem to crack with my procedural PHP, direct mysql_query background. It basically involves the Eloquent ORM over multiple tables.

I have 3 tables (Users, User_Profiles, and User_Answers). The Users table only keeps the very basics of the user (auto_incremented id, email, password), the User_Profiles table contains a few more details (image url, country, city, gender, etc) and belongs_to the User model. The User_Answers table is a list of answers given by the user and also belongs_to the User model.

What I would like to do is select all rows from the User_Profiles table where the city is the same as the city of the logged-in user, get their user_id's in an array and then compare the answers (from the User_Answers table) to the answers of the currently logged in User. The following is what I'm looking to do but in plain PHP and (for explanation purposes only) mysql_query. I apologize in advance for the awful code. I just need to be pointed in the right direction.

<?php

$link = mysql_connect("localhost", "xxx", "xxx");
$db = mysql_select_db('testersize', $link);

$id = 2;
$sql = "SELECT city FROM user_profiles WHERE user_id = $id";
$query = mysql_query($sql, $link);

$row = mysql_fetch_row($query);

$city = $row[0];

echo $city . "</br>";

$sql = "SELECT user_id FROM user_profiles WHERE city = '$city'";
$matches = mysql_query($sql, $link);

//

while($row = mysql_fetch_row($matches)){
  $u_id = $row[0];
  $sql = "SELECT books, movies, music FROM user_answers WHERE user_id = $u_id";
  $query2 = mysql_query($sql, $link);
  $row2 = mysql_fetch_row($query2);
  echo "<h2>User Number: " . $u_id . "</h2>";
  echo "your favorite books:" . $row2[0] . "</br>";
  echo "your favorite movies:" . $row2[1] . "</br>";
  echo "your favorite music:" . $row2[2] . "</br>";
}
?>

$user_profiles = User_Profiles::where('city','=',Auth::user()->city)->get();
foreach($user_profiles as $user_profile){
  $id = array('user_id'=>$user_profile->user_id);
}

So that code will get you the user_profiles by city and then loop through them and put their in an array , im not sure what do you mean by match answers to users table though..

$user_ids = User_Profiles::where('city','=',Auth::user()->city)->lists('user_id');
$favorites = User_Answers::whereIn('user_id',$user_ids)->get();
foreach($favorites as $favorite)
{
    echo $favorite->book;
    echo $favorite->music;
    echo $favorite->movie;
}