from HDM rendering

place.sql

(SELECT 
    way, 
    CASE 
      WHEN place='country' THEN 1 
      WHEN place='state' THEN 10 
      WHEN tags->'is_capital'='country' THEN 20 
      WHEN place='city' THEN 21 
      WHEN place='town' THEN 30 
      ELSE 100 
    END as prio, 
    place AS type, 
    name, 
    z_order, 
    CASE 
      WHEN population ~ E'^\\\\d+$' THEN population::integer 
      ELSE 0
    END AS population,
    tags->'is_capital' as is_capital
  FROM planet_osm_point 
  WHERE 
    place in ('country', 'state', 'city', 'town') 
    AND place IS NOT NULL 
  ORDER BY prio, population DESC NULLS LAST) 
AS data