Fixes #418

src/Jenssegers/Mongodb/Query/Builder.php

@@ -3,6 +3,7 @@
 use MongoId, MongoRegex, MongoDate, DateTime, Closure;
 use Illuminate\Database\Query\Builder as BaseBuilder;
 use Illuminate\Database\Query\Expression;
+use Illuminate\Support\Collection;
 use Jenssegers\Mongodb\Connection;
 
 class Builder extends BaseBuilder {
@@ -549,6 +550,33 @@ class Builder extends BaseBuilder {
         return (1 == (int) $result['ok']);
     }
 
+    /**
+     * Get an array with the values of a given column.
+     *
+     * @param  string  $column
+     * @param  string  $key
+     * @return array
+     */
+    public function lists($column, $key = null)
+    {
+        if ($key == '_id')
+        {
+            $results = new Collection($this->get([$column, $key]));
+
+            // Convert MongoId's to strings so that lists can do its work.
+            $results = $results->map(function($item)
+            {
+                $item['_id'] = (string) $item['_id'];
+
+                return $item;
+            });
+
+            return $results->lists($column, $key);
+        }
+
+        return parent::lists($column, $key);
+    }
+
     /**
      * Create a raw database expression.
      *

tests/QueryBuilderTest.php

@@ -370,6 +370,10 @@ class QueryBuilderTest extends TestCase {
 		$list = DB::collection('items')->lists('type', 'name');
 		$this->assertEquals(3, count($list));
 		$this->assertEquals(array('knife' => 'sharp', 'fork' => 'sharp', 'spoon' => 'round'), $list);
+
+		$list = DB::collection('items')->lists('name', '_id');
+		$this->assertEquals(4, count($list));
+		$this->assertEquals(24, strlen(key($list)));
 	}
 
 	public function testAggregate()