显示出昨天，今天，明天，精度到时，分，秒，下列sql语句正确的是：( )
alter table set nls_date_format = 'yyyy mm dd hh24:mi:ss';
select yesterday,today, tomorrow from dual;
alter session set nls_date_format = 'yyyy mm dd hh24:mi:ss';
select yesterday,today, tomorrow from dual;
alter table set nls_date_format = 'yyyy mm dd hh24:mi:ss';
select sysdate-1,sysdate,sysdate+1 from dual;
alter session set nls_date_format = 'yyyy mm dd hh24:mi:ss';
select sysdate-1,sysdate,sysdate+1 from dual;
