Hive学习三

Hive学习三

标签（空格分隔）： Hive

一， load方式加载数据，注意分区表加载数据的特殊性

1， 创建普通表并加载数据

create table if not exists emp(empno int,ename string,job string,mgr int,hiredate string,sal double,comm double,deptno int) row format delimited fields terminated by '\t' stored as textfile;

load data local inpath '/opt/datas/emp.txt' into table emp ；//加载本地数据并查询数据

2， 创建分区表：

CREATE TABLE IF NOT EXISTS emp_day( empno int, ename string, job string, mgr int, hiredate string, sal double, comm double, deptno int) partitioned by (day string) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' STORED AS TEXTFILE ;

load data local inpath '/opt/datas/emp.txt' into table emp_day partition(day='0312');//加载数据并查询

二，将hive查询结果保存到表中和本地

1， 保存查询结果到另一个hive表中

insert into emp_other select * from emp;

2， 导出结果到本地文件中

insert overwrite local directory '/opt/datas/emp_export0312' ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' select * from emp;

3， 导出结果到hdfs系统

insert overwrite directory 'emp_export0312' select * from emp;

三,常见查询练习，如group by having join sort by order by等

1，  select empno,ename,deptno from emp where deptno=30;

2，  select empno,ename,deptno from emp limit 3;

3，  select deptno,avg(sal),sum(sal) from emp group by deptno;

4,select deptno,avg(sal) avg_sal from emp group by deptno having avg_sal>1000;

5, select e.empnp,e.ename,d,deptno,d.dname from emp e join dept d on e.deptno=d.deptno;

6,select * from emp order by empno desc;