delete from emp;
insert into emp values(null, '鈴木義男', null, null, '11-1111');
insert into emp values(564002, '斎藤洋子', null, null, null);
insert into emp values(null, '山田美樹', null, 33, null);
insert into emp values(564004, '田中秀明', null, null, '44-4444');