diff --git a/src/wp-includes/query.php b/src/wp-includes/query.php
index 2adf7d2168..05d4979d4f 100644
--- a/src/wp-includes/query.php
+++ b/src/wp-includes/query.php
@@ -2268,7 +2268,7 @@ class WP_Query {
 			// This overrides posts_per_page.
 			if ( ! empty( $q['posts_per_rss'] ) ) {
 				$q['posts_per_page'] = $q['posts_per_rss'];
-			} else { 
+			} else {
 				$q['posts_per_page'] = get_option( 'posts_per_rss' );
 			}
 			$q['nopaging'] = false;
@@ -3205,7 +3205,7 @@ class WP_Query {
 			$this->post_count = count( $this->posts );
 			$this->set_found_posts( $q, $limits );
 
-			return $this->posts;
+			return array_map( 'intval', $this->posts );
 		}
 
 		if ( 'id=>parent' == $q['fields'] ) {
@@ -3214,9 +3214,9 @@ class WP_Query {
 			$this->set_found_posts( $q, $limits );
 
 			$r = array();
-			foreach ( $this->posts as $post )
-				$r[ $post->ID ] = $post->post_parent;
-
+			foreach ( $this->posts as $post ) {
+				$r[ (int) $post->ID ] = (int) $post->post_parent;
+			}
 			return $r;
 		}
 
diff --git a/tests/phpunit/tests/query/results.php b/tests/phpunit/tests/query/results.php
index 4593c14311..20c45ba446 100644
--- a/tests/phpunit/tests/query/results.php
+++ b/tests/phpunit/tests/query/results.php
@@ -46,10 +46,10 @@ class Tests_Query_Results extends WP_UnitTestCase {
 		$this->parent_one = $this->factory->post->create( array( 'post_title' => 'parent-one', 'post_date' => '2007-01-01 00:00:00' ) );
 		$this->parent_two = $this->factory->post->create( array( 'post_title' => 'parent-two', 'post_date' => '2007-01-01 00:00:00' ) );
 		$this->parent_three = $this->factory->post->create( array( 'post_title' => 'parent-three', 'post_date' => '2007-01-01 00:00:00' ) );
-		$this->factory->post->create( array( 'post_title' => 'child-one', 'post_parent' => $this->parent_one, 'post_date' => '2007-01-01 00:00:01' ) );
-		$this->factory->post->create( array( 'post_title' => 'child-two', 'post_parent' => $this->parent_one, 'post_date' => '2007-01-01 00:00:02' ) );
-		$this->factory->post->create( array( 'post_title' => 'child-three', 'post_parent' => $this->parent_two, 'post_date' => '2007-01-01 00:00:03' ) );
-		$this->factory->post->create( array( 'post_title' => 'child-four', 'post_parent' => $this->parent_two, 'post_date' => '2007-01-01 00:00:04' ) );
+		$this->child_one = $this->factory->post->create( array( 'post_title' => 'child-one', 'post_parent' => $this->parent_one, 'post_date' => '2007-01-01 00:00:01' ) );
+		$this->child_two = $this->factory->post->create( array( 'post_title' => 'child-two', 'post_parent' => $this->parent_one, 'post_date' => '2007-01-01 00:00:02' ) );
+		$this->child_three = $this->factory->post->create( array( 'post_title' => 'child-three', 'post_parent' => $this->parent_two, 'post_date' => '2007-01-01 00:00:03' ) );
+		$this->child_four = $this->factory->post->create( array( 'post_title' => 'child-four', 'post_parent' => $this->parent_two, 'post_date' => '2007-01-01 00:00:04' ) );
 
 		unset( $this->q );
 		$this->q = new WP_Query();
@@ -370,6 +370,38 @@ class Tests_Query_Results extends WP_UnitTestCase {
 		), wp_list_pluck( $posts, 'post_title' ) );
 	}
 
+	/**
+	 * @ticket 27252
+	 */
+	function test_query_fields_integers() {
+
+		$parents = array(
+			(int) $this->parent_one,
+			(int) $this->parent_two
+		);
+		$posts1 = $this->q->query( array(
+			'post__in'  => $parents,
+			'fields'    => 'ids',
+			'orderby'   => 'post__in',
+		) );
+
+		$this->assertSame( $parents, $posts1 );
+
+		$children = array(
+			(int) $this->child_one => (int) $this->parent_one,
+			(int) $this->child_two => (int) $this->parent_one
+		);
+
+		$posts2 = $this->q->query( array(
+			'post__in'  => array_keys( $children ),
+			'fields'    => 'id=>parent',
+			'orderby'   => 'post__in',
+		) );
+
+		$this->assertSame( $children, $posts2 );
+
+	}
+
 	function test_exlude_from_search_empty() {
 		global $wp_post_types;
 		foreach ( array_keys( $wp_post_types ) as $slug )