多选题 分析下面三条语句：
create view v1 as select department_id,department_name,last_name from
departments join employees using(department_id);
select department_name,last_name from v1 where department_id=20;
select d.department_name,e.last_name from departments d, employees e
where d.department_id=e.department_id and
d.department_id=20;
第一个查询会比第二个查询快，因为：