嗨喽，各位同学又到了公布CDA数据分析师认证考试LEVEL I的模拟试题时间了，今天给大家带来的是模拟试题（二）中的1-5题。

1.在以下语句中，哪个是降序查询t1表中不同城市pm10的平均值（）

A.select city_name,avg(pm10) from t1group by city_nameorder by avg(pm10) desc;

B.select city_name,mean(pm10) from t1group by city_nameorder by avg(pm10) desc;

C.select city_name,avg(pm10) from t1group by city_nameorder by avg(pm10) asc;

D.select city_name,avg(pm10) from t1group by city_nameorder by avg(pm10);

2.在以下语句中，哪个语句可以用来查询表中‘员工id’字段以’b’开头的记录

A.select * from 绩效成绩 where 员工id = ‘b’;

B.select * from 绩效成绩 where 员工id regexp ‘^b’;

C.select * from 绩效成绩 where 员工id = ‘^b’;

D.select * from 绩效成绩 where 员工id regexp ‘.b’;

3.参照以下信息选择能够正确创建orderinfo表的语句

A.create table orderinfo(orderid char(6) not null unique primary key,price decimal not null,amount int not null);

B.create table orderinfo(orderid varchar(6) not null unique primary key,price float not null,amount int not null);

C.create orderinfo(orderid varchar(6) not null unique primary key,price float not null,amount int not null);

D.create orderinfo(orderid char(6) not null unique primary key,price float not null,amount int not null);

4.下列涉及通配符的操作，范围最大的是( )

A.name like ’hgf#’B.name like ’hgf_t%’

C.name like ’hgf%’

D.name like ’hgf_’

5.以下哪个语句不能查询出结果

A.select * from 订单 where 销售数量>5 order by 销售金额

B.select * from 订单 where 销售数量>5 and销售数量5 or 销售数量