根据教材中的用户表,并完成以下sql查询
-- 查询姓李的
select *from user where name like '李%';
-- 查询北京用户
select * from user where city='北京';
-- 修改郭玉的信用积分设置为240
update user set credit=240 where name='郭玉';
select* from user;
-- 删除郭玉的英文姓名
update user set ename=null where name='郭玉';
select* from user;
-- 将所有用户的信用积分减1
update user set credit=credit-1;
select * from user;
-- 删除所有信用积分低于300的用户
DELETE from user where credit<300;
select * from user;