2.4 hive创建表实例讲解

一、create table

##
员工表
create table IF NOT EXISTS default.emp(
empno int,
ename string,
job string,
mgr int,
hiredate string,
sal double,
comm double,
deptno int
)
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';

##
部门表
create table IF NOT EXISTS default.dept(
deptno int,
dname string,
loc string
)
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';

#查看
hive (default)> show tables;
OK
tab_name
...
dept
emp

2、加载数据

#emp
hive (default)> load data local inpath '/opt/datas/emp.txt' overwrite into table emp ;

#dept
hive (default)> load data local inpath '/opt/datas/dept.txt' overwrite into table dept ;

#select
hive (default)> select * from emp;
OK
emp.empno    emp.ename    emp.job    emp.mgr    emp.hiredate    emp.sal    emp.comm    emp.deptno
7369    SMITH    CLERK    7902    1980-12-17    800.0    NULL    20
7499    ALLEN    SALESMAN    7698    1981-2-20    1600.0    300.0    30
7521    WARD    SALESMAN    7698    1981-2-22    1250.0    500.0    30
7566    JONES    MANAGER    7839    1981-4-2    2975.0    NULL    20
7654    MARTIN    SALESMAN    7698    1981-9-28    1250.0    1400.0    30
7698    BLAKE    MANAGER    7839    1981-5-1    2850.0    NULL    30
7782    CLARK    MANAGER    7839    1981-6-9    2450.0    NULL    10
7788    SCOTT    ANALYST    7566    1987-4-19    3000.0    NULL    20
7839    KING    PRESIDENT    NULL    1981-11-17    5000.0    NULL    10
7844    TURNER    SALESMAN    7698    1981-9-8    1500.0    0.0    30
7876    ADAMS    CLERK    7788    1987-5-23    1100.0    NULL    20
7900    JAMES    CLERK    7698    1981-12-3    950.0    NULL    30
7902    FORD    ANALYST    7566    1981-12-3    3000.0    NULL    20
7934    MILLER    CLERK    7782    1982-1-23    1300.0    NULL    10
Time taken: 0.029 seconds, Fetched: 14 row(s)

hive (default)> select * from dept;
OK
dept.deptno    dept.dname    dept.loc
10    ACCOUNTING    NEW YORK
20    RESEARCH    DALLAS
30    SALES    CHICAGO
40    OPERATIONS    BOSTON
Time taken: 0.028 seconds, Fetched: 4 row(s)

二、创建一个表通过子查询

#创建
hive (default)> create table if not exists default.dept_cats as select * from dept;

#查
hive (default)> select * from dept_cats;
OK
dept_cats.deptno    dept_cats.dname    dept_cats.loc
10    ACCOUNTING    NEW YORK
20    RESEARCH    DALLAS
30    SALES    CHICAGO
40    OPERATIONS    BOSTON
Time taken: 0.026 seconds, Fetched: 4 row(s)

三、清除一个表

##
hive (default)> truncate table dept_cats;
OK
Time taken: 0.037 seconds

hive (default)> select * from dept_cats;
OK
dept_cats.deptno    dept_cats.dname    dept_cats.loc
Time taken: 0.026 seconds

四、alter、删除

#先创建一个表
hive (default)> create table if not exists default.dept_like like default.dept ;
OK
Time taken: 0.04 seconds

#alter
hive (default)> alter table dept_like rename to dept_like_rename;
OK
Time taken: 0.088 seconds

#删除
hive (default)> drop table if exists dept_like_rename ;
Moved: 'hdfs://hadoop-senior.ibeifeng.com:8020/user/hive/warehouse/dept_like_rename' to trash at: hdfs://hadoop-senior.ibeifeng.com:8020/user/root/.Trash/Current
OK
Time taken: 0.346 seconds