diff --git a/phpBB/includes/cache/driver/interface.php b/phpBB/includes/cache/driver/interface.php
index 6adc95a86a..d403bbcd71 100644
--- a/phpBB/includes/cache/driver/interface.php
+++ b/phpBB/includes/cache/driver/interface.php
@@ -63,12 +63,12 @@ interface phpbb_cache_driver_interface
 	public function destroy($var_name, $table = '');
 
 	/**
-	* Check if a given cache entry exist
+	* Check if a given cache entry exists
 	*/
 	public function _exists($var_name);
 
 	/**
-	* Load cached sql query
+	* Load result of an SQL query from cache.
 	*
 	* @param string $query			SQL query
 	*
@@ -79,7 +79,11 @@ interface phpbb_cache_driver_interface
 	public function sql_load($query);
 
 	/**
-	* Save sql query
+	* Save result of an SQL query in cache.
+	*
+	* In persistent cache stores, this function stores the query
+	* result to persistent storage. In other words, there is no need
+	* to call save() afterwards.
 	*
 	* @param string $query			SQL query, should be used for generating storage key
 	* @param mixed $query_result	The result from dbal::sql_query, to be passed to
@@ -94,7 +98,7 @@ interface phpbb_cache_driver_interface
 	public function sql_save($query, $query_result, $ttl);
 
 	/**
-	* Ceck if a given sql query exist in cache
+	* Check if result for a given SQL query exists in cache.
 	*
 	* @param int $query_id
 	* @return bool
diff --git a/phpBB/includes/cache/driver/memory.php b/phpBB/includes/cache/driver/memory.php
index bc08494c0c..e4da5767cf 100644
--- a/phpBB/includes/cache/driver/memory.php
+++ b/phpBB/includes/cache/driver/memory.php
@@ -294,7 +294,7 @@ abstract class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 		if (!preg_match('/FROM \\(?(`?\\w+`?(?: \\w+)?(?:, ?`?\\w+`?(?: \\w+)?)*)\\)?/', $query, $regs))
 		{
 			// Bail out if the match fails.
-			return;
+			return $query_result;
 		}
 		$tables = array_map('trim', explode(',', $regs[1]));
 
diff --git a/tests/cache/cache_test.php b/tests/cache/cache_test.php
index c5f5fac88c..c904aa6c41 100644
--- a/tests/cache/cache_test.php
+++ b/tests/cache/cache_test.php
@@ -89,20 +89,55 @@ class phpbb_cache_test extends phpbb_database_test_case
 			WHERE config_name = 'foo'";
 		$result = $db->sql_query($sql, 300);
 		$first_result = $db->sql_fetchrow($result);
+		$expected = array('config_name' => 'foo', 'config_value' => '23', 'is_dynamic' => 0);
+		$this->assertEquals($expected, $first_result);
 
 		$this->assertFileExists($this->cache_dir . 'sql_' . md5(preg_replace('/[\n\r\s\t]+/', ' ', $sql)) . '.php');
 
+		$sql = "DELETE FROM phpbb_config";
+		$result = $db->sql_query($sql);
+
 		$sql = "SELECT * FROM phpbb_config
 			WHERE config_name = 'foo'";
 		$result = $db->sql_query($sql, 300);
 
-		$this->assertEquals($first_result, $db->sql_fetchrow($result));
+		$this->assertEquals($expected, $db->sql_fetchrow($result));
 
 		$sql = "SELECT * FROM phpbb_config
-			WHERE config_name = 'bar'";
+			WHERE config_name = 'foo'";
+		$result = $db->sql_query($sql);
+
+		$no_cache_result = $db->sql_fetchrow($result);
+		$this->assertSame(false, $no_cache_result);
+
+		$db->sql_close();
+	}
+
+	public function test_null_cache_sql()
+	{
+		$driver = new phpbb_cache_driver_null($this->cache_dir);
+
+		global $db, $cache;
+		$db = $this->new_dbal();
+		$cache = new phpbb_cache_service($driver);
+
+		$sql = "SELECT * FROM phpbb_config
+			WHERE config_name = 'foo'";
+		$result = $db->sql_query($sql, 300);
+		$first_result = $db->sql_fetchrow($result);
+		$expected = array('config_name' => 'foo', 'config_value' => '23', 'is_dynamic' => 0);
+		$this->assertEquals($expected, $first_result);
+
+		$sql = "DELETE FROM phpbb_config";
+		$result = $db->sql_query($sql);
+
+		// As null cache driver does not actually cache,
+		// this should return no results
+		$sql = "SELECT * FROM phpbb_config
+			WHERE config_name = 'foo'";
 		$result = $db->sql_query($sql, 300);
 
-		$this->assertNotEquals($first_result, $db->sql_fetchrow($result));
+		$this->assertSame(false, $db->sql_fetchrow($result));
 
 		$db->sql_close();
 	}