5分钟学会操作hive

查看所有数据库

show databases;

使用正则筛选数据库名(使用x开头的数据库)

show databases like 'x.*';

创建数据库

create database xtt;

防止报错

create database if not exists xtt;

添加描述

create database xtt2 comment 'is xtt2';

查看数据库

descride database xtt;

删除数据库

只能删除没有表的数据库

drop database xtt;

有表的数据库要添加cascade关键字，hive会先删除数据库中 表，然后就可以删除数据库了

drop database if exists xtt cascade;

使用数据库

use xtt;

小练习

创建并使用school数据库，创建内部表student(id bigint, name string, score double, age int) 并加载数据文件student.txt到student表
建表语句

create table student(id bigint, name string, score double, age int) row format delimited fields terminated by ',' location '/student';

加载数据

load data local inpath '/root/student.txt' into table student;

在school数据库创建外部表student_external(id bigint, name string, score double, age int) ，并加载数据文件student.txt到student_external表
建表语句

create external table student_external(id bigint, name string, score double, age int) row format delimited fields terminated by ',' location '/student_external';

加载数据

load data local inpath '/root/student.txt' into table student_external;

创建并使用shop数据库，以sex string列为分区列创建分区表customer_partition(name string, age int)
创建并使用数据库

create database if not exists shop;use shop;

建表语句

create table customer_partition(name string, age int) partitioned by(sex string) row format delimited fields terminated by 't';

以静态分区方式先将数据文件customer.txt加载到分区表customer_partition的指定分区(sex=man)中，再将数据文件ccustomer_1.txt加载到分区表customer_partition的指定分区(sex=woman)中

load data local inpath '/root/customer.txt' into table customer_partition partition(sex='man');load data local inpath '/root/customer_1.txt' into table customer_partition partition(sex='woman');

创建外部表customer_external(name string, age int) 并加载数据文件customer_external.txt到customer_external表

create external table customer_external(name string, age int) row format delimited fields terminated by 't';load data local inpath '/root/customer_external.txt' into table customer_external;

以sex和native 两列为分区列创建分区表customer_partion_dynamic；再以动态分区方式，将customer_external表的数据动态插入到分区表customer_partition_dynamic
第三题不对劲，好像搞错了，这题写不了

先创建并使用sogou数据库，再创建内部表sogou500w( ts string, uid string, keyword string, rank int, orders int, url string) ，再加载本地数据文件sogou.500w.utf8到sogou500w表

create database sogou;

use sogou;

create table if not exists sogou500w( ts string, uid string, keyword string, rank int, orders int, url string) row format delimited fields terminated by 't' ;

load data local inpath '/root/sogou.500w.utf8' overwrite into table sogou500w;

2 查询sogou500w表，用where语句筛选出关键词keword包含"baidu"的前10行数据

select * from sogou500w where keyword like 'baidu' limit 10;

3 使用group语句、having语句和count函数，统计keyword包含"baidu"的每个用户uid的搜索次数大于10次的uid和搜索次数

select uid, count(*) as cnt from sogou500w where keyword like 'baidu' group by uid, keyword having cnt>10;

4 使用order by语句，统计所有用户uid的搜索次数，并列出搜索次数排前10位的用户uid和搜索次数

select uid, count(*) as cnt from sogou500w group by uid order by cnt desc limit 10;

逢考必过一键三连