[SMALL PATCH] Sql sensor (#12242)

* Initial Commit

* Passed all checks

* Make DB_URL required

* addresses review comments from @fabaff

* unused variable

* return nothing

homeassistant/components/sensor/sql.py

@@ -134,7 +134,7 @@ class SQLSensor(Entity):
 
         if data is None:
             _LOGGER.error("%s returned no results", self._query)
-            return False
+            return
 
         if self._template is not None:
             self._state = self._template.async_render_with_possible_json_value(