sql语句练习:找出平均工资小于5000的商店所在的城市
员工信息表 employee： user_id , name, store_id, salary
商店表stores：store_id, name,city
参考答案：select a.city from stores a,employee b where b.store_id=a.store_id group by b.store_id having avg(b.salary)<5000
员工信息表 employee： user_id , name, store_id, salary
商店表stores：store_id, name,city
参考答案：select a.city from stores a,employee b where b.store_id=a.store_id group by b.store_id having avg(b.salary)<5000
