text: DROP TABLE IF EXISTS t_map_null;
  
  SET allow_experimental_map_type = 1;
  
  CREATE TABLE t_map_null (a Map(String, String), b String) engine = MergeTree() ORDER BY a;
  INSERT INTO t_map_null VALUES (map('a', 'b', 'c', 'd'), 'foo');
  SELECT count() FROM t_map_null WHERE a = map('name', NULL, '', NULL);
  
  DROP TABLE t_map_null;
  