ATTACH DATABASE 'hash2.db' AS ha_2;
ATTACH DATABASE 'hash3.db' AS ha_3;

SELECT name, SUM(value) FROM (
  SELECT * FROM main.kv_store UNION ALL
  SELECT * FROM ha_2.kv_store UNION ALL
  SELECT * FROM ha_3.kv_store
) GROUP BY name ORDER BY SUM(value) DESC, name;

DETACH DATABASE ha_2;
DETACH DATABASE ha_3;