diff --git a/layers/housenumber/housenumber_centroid.sql b/layers/housenumber/housenumber_centroid.sql
index 8a81d6a..101f701 100644
--- a/layers/housenumber/housenumber_centroid.sql
+++ b/layers/housenumber/housenumber_centroid.sql
@@ -1,4 +1,9 @@
 
 -- etldoc: osm_housenumber_point -> osm_housenumber_point
-UPDATE osm_housenumber_point SET geometry=topoint(geometry)
-WHERE ST_GeometryType(geometry) <> 'ST_Point';
+CREATE FUNCTION convert_housenumber_point() RETURNS VOID AS $$
+BEGIN
+  UPDATE osm_housenumber_point SET geometry=topoint(geometry) WHERE ST_GeometryType(geometry) <> 'ST_Point';
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT convert_housenumber_point();