text: /*
    From the paper: http://www09.sigmod.org/sigmod/record/issues/0809/p23.grant.pdf
    Flaw in SQL pointed out by CJ Date.
  */
  drop database if exists null_values;
  create database null_values;
  use null_values;
  
  create table suppliers(sno varchar(30), city varchar(20));
  create table parts(pno varchar(30), city varchar(20));
  
  insert into suppliers (sno, city) values ('S1', 'London');
  insert into parts (pno) values ('P1');
  
  select sno, pno from suppliers, parts where suppliers.city <> parts.city or parts.city <> 'Paris';
  