text: SELECT toFixedString('', 4) AS str, empty(str) AS is_empty;
  SELECT toFixedString('\0abc', 4) AS str, empty(str) AS is_empty;
  
  DROP TABLE IF EXISTS test.defaulted;
  CREATE TABLE test.defaulted (v6 FixedString(16)) ENGINE=Memory;
  INSERT INTO test.defaulted SELECT toFixedString('::0', 16) FROM numbers(32768);
  SELECT count(), notEmpty(v6) e FROM test.defaulted GROUP BY e;
  DROP TABLE test.defaulted;
  