CTEs always materialise so inline the union zoom level views ⚠️

schema/layers/urban.sql

@@ -16,7 +16,7 @@ CREATE OR REPLACE VIEW urban_z6 AS (
 
 CREATE OR REPLACE FUNCTION layer_urban(bbox geometry, zoom_level int)
 RETURNS TABLE(geom geometry, scalerank int) AS $$
-    WITH zoom_levels AS (
+    SELECT geom, scalerank FROM (
         SELECT * FROM urban_z4
         WHERE zoom_level = 4
         UNION ALL
@@ -25,7 +25,6 @@ RETURNS TABLE(geom geometry, scalerank int) AS $$
         UNION ALL
         SELECT * FROM urban_z6
         WHERE zoom_level >= 6 AND scalerank-1 <= zoom_level
-    )
-    SELECT geom, scalerank FROM zoom_levels
+    ) AS zoom_levels
     WHERE geom && bbox;
 $$ LANGUAGE SQL IMMUTABLE;