select * from user where city='北京' order by credit;
select * from user where sex='男' order by personId desc;
select * from user where ename like '%' order by ename;
select city,count(city) from user group by city;
select sex, avg(credit) from user group by sex;
select * from user order by credit desc limit 0,3;
select * from user where sex='男' order by credit limit 0,3;
select city,avg(credit) c from user group by city having c>350 ;