目录
建表语句
表数据
Hive建表高阶语句 - CTAS and WITH
CTAS – as select方式建表
CTE (CTAS with Common Table Expression)
LIKE
创建临时表
清空表数据
修改表（Alter针对元数据）
改名
修正表文件格式
修改列名
添加列
替换列
动态分区
使用动态分区需设定属性
建表语句
动态分区插入数据
查询分区
添加分区
删除分区
建表语句
create table if not exists employee
(
name string,
workplace array<string>,
gender string,
age int,
skills_score map<string,int>,
depart_title map<string,string>
) row format delimited fields terminated by '|'
collection items terminated by ','
map keys terminated by ':'
lines terminated by '\n';表数据
Michael|Montreal,Toronto|Male|30|DB:80|Product:Developer Lead
Will|Montreal|Male|35|Perl:85|Product:Lead,Test:Lead
Shelley|New York|Female|27|Python:80|Test:Lead,COE:Architect
Lucy|Vancouver|Female|57|Sales:89,HR:94|Sales:Lead
Hive建表高阶语句 - CTAS and WITH
CTAS – as select方式建表
CREATE TABLE ctas_employee as SELECT * FROM employee;
CTAS不能创建partition, external, bucket table
CTE (CTAS with Common Table Expression)
CREATE TABLE cte_employee AS
WITH
r1 AS (SELECT name FROM r2 WHERE name = 'Michael'),
r2 AS (SELECT name FROM employee WHERE gender= 'Male'),
r3 AS (SELECT name FROM employee WHERE gender = 'Female')
SELECT * FROM r1 UNION ALL SELECT * FROM r3;LIKE
CREATE TABLE employee_like LIKE employee;
创建临时表
临时表是应用程序自动管理在复杂查询期间生成的中间数据的方法
表只对当前session有效，session退出后自动删除
表空间位于/tmp/hive-<user_name>(安全考虑)
如果创建的临时表表名已存在，实际用的是临时表
CREATE TEMPORARY TABLE tmp_table_name1 (c1 string);
CREATE TEMPORARY TABLE tmp_table_name2 AS..
CREATE TEMPORARY TABLE tmp_table_name3 LIKE..
清空表数据
TRUNCATE TABLE employee;
修改表（Alter针对元数据）
改名
ALTER TABLE employee RENAME TO new_employee;
修正表文件格式
ALTER TABLE employee SET FILEFORMAT RCFILE;
修改列名
ALTER TABLE employee CHANGE name employee_name STRING;
添加列
ALTER TABLE employee ADD COLUMNS (work string);
替换列
ALTER TABLE employee REPLACE COLUMNS (name string);
创建分区
动态分区
使用动态分区需设定属性
set hive.exec.dynamic.partition=true;
set hive.exec.dynamic.partition.mode=nonstrict;
建表语句
create table employee_dt(
name string,
workplace array<string>,
skills_score map<string,int>,
depart_title map<string,string>
) partitioned by (gender string,age int )
row format delimited fields terminated by ','
collection items terminated by '-'
map keys terminated by ':'
lines terminated by "\n";动态分区插入数据
insert into table employee_dt partition (gender,age)
select name, workplace, skills_score, depart_title, gender, age
from employee2;查询分区
show partitions employee_dt;
添加分区
alter table employee_dt
add partition (gender = "Male",age = 28);
删除分区
alter table employee_dt
drop partition (gender = "Male",age = 28);
