text: select 1 from db_root where 1 IS NULL;
  select 1 from db_root where 's' IS NULL;
  select 1 from db_root where '1' IS NULL;
  select 1 from db_root where 0 IS NULL;
  select 1 from db_root where NULL IS NULL;
  select 1 from db_root where 123456789012345 is null;