text: SELECT 1 from db_root where 1 <=> 1;
  SELECT 1 from db_root where  NULL <=> NULL;
  SELECT 1 from db_root where 1 <=> NULL;
  
  SELECT 1 from db_root where '1' <=> 1;
  SELECT 1 from db_root where '1' <=> '1';
  SELECT 1 from db_root where  '1' <=> NULL;
  
  SELECT 1 from db_root where 1 = 1;
  SELECT 1 from db_root where NULL = NULL;
  SELECT 1 from db_root where 1 = NULL;
  
  SELECT 1 from db_root where '1' = 1;
  SELECT 1 from db_root where '1' = '1';
  SELECT 1 from db_root where 1 = NULL;
  
  SELECT 1 from db_root where 123456789012345 <=> 1283241243123;
  
  SELECT 1 from db_root where 123456789012345 <=> null;
  