Hive ----DDL

1、创建数据库

create database test_db comment 'test database';
create database if not exists test_db comment 'test database';
create database test_db location 'hdfs path';
create database test_db with dbproperties('creator'='bpf','date'='20171106');

2、查看数据库

show databases;
show databases like 'test*';

3、查看具体数据库结构

describe database test_db;
describe database extended test_db;

4、使用（切换）数据库

use test_db

5、删除数据库

drop database if exists test_db;
drop database if exists test_db cascade; 

6、创建表

create table [if not exists] [test_db.]test_table(
  a string [comment 'string field'],
  b float [comment 'float field'],
  c array [comment 'array field'],
  d mapint> [comment 'map field'],
  e structint> [comment 'struct field']
)
[comment 'description for this table']
[tblproperties ('k1' = 'v1', 'k2' ='v2')]
[row format delimited
fields terminated by '\001'
collection items terminated by '\002'
map keys terminated by '\003']
[lines terminated by '\t']
[store as textfile]
[location 'hdfs path']
[as select_statement];   -- (这句不支持外部表) 

create table [if not exists] [test_db.]test_table like [test_db.]other_table [location 'hdfs path'] 

7、数据类型

data_type
  : primitive_type
  | array_type
  | map_type
  | struct_type
  | union_type  -- (Note: Available in Hive 0.7.0 and later)

primitive_type
  : TINYINT
  | SMALLINT
  | INT
  | BIGINT
  | BOOLEAN
  | FLOAT
  | DOUBLE
  | DOUBLE PRECISION -- (Note: Available in Hive 2.2.0 and later)
  | STRING
  | BINARY      -- (Note: Available in Hive 0.8.0 and later)
  | TIMESTAMP   -- (Note: Available in Hive 0.8.0 and later)
  | DECIMAL     -- (Note: Available in Hive 0.11.0 and later)
  | DECIMAL(precision, scale)  -- (Note: Available in Hive 0.13.0 and later)
  | DATE        -- (Note: Available in Hive 0.12.0 and later)
  | VARCHAR     -- (Note: Available in Hive 0.12.0 and later)
  | CHAR        -- (Note: Available in Hive 0.13.0 and later)

array_type
  : ARRAY < data_type >

map_type
  : MAP < primitive_type, data_type >

struct_type
  : STRUCT < col_name : data_type [COMMENT col_comment], ...>

union_type
   : UNIONTYPE < data_type, data_type, ... >  -- (Note: Available in Hive 0.7.0 and later)

8、文件格式

file_format:
  : SEQUENCEFILE
  | TEXTFILE    -- (Default, depending on hive.default.fileformat configuration)
  | RCFILE      -- (Note: Available in Hive 0.6.0 and later)
  | ORC         -- (Note: Available in Hive 0.11.0 and later)
  | PARQUET     -- (Note: Available in Hive 0.13.0 and later)
  | AVRO        -- (Note: Available in Hive 0.14.0 and later)
  | INPUTFORMAT input_format_classname OUTPUTFORMAT output_format_classname

9、查看可用表

show tables;
show tables in test_db;
show tables like 'test*';

10、查看表tblproperties

show tblproperties test_db;

11、查看表详细信息

desc test_table;
desc extended test_table;
desc formatted test_table;

12、查看表中某一列的信息

desc test_table.column;

13、创建外部表

create external table if not exists test_table(
  field string
)
[as select_statement]不可用

14、创建分区表

create table test)table(
  field string
)
partitioned by (k1 string, k2 int);
//分区后会在hdfs中的表对应的目录下生成子目录 k1/k2，便于管理分类，针对性查询时也可以提高性能

15、查看表中的分区

show partitions test_db;
show partitions test_table partition(k1='value');

16、加载数据到分区表

load data [local] inpath 'path/file' into table test_table partition(k1='v1',k2='v2');
//有Local代表本地路径，没有代表HDFS路径

17、增加分区

alter table test_table add partition(...) location 'hdfs path'

18、修改分区对应的目录地址

alter table test_table partition(k1=v1, k2=v2) set location 'hdfs path';

19、删除分区

alter table test_table drop if exists partition(...);

20、修改表

ALTER TABLE name RENAME TO new_name
ALTER TABLE name ADD COLUMNS (字段1及其属性，字段2及其属性)
ALTER TABLE name DROP [COLUMN] column_name
ALTER TABLE name CHANGE column_name new_name new_type

21、删除表

DROP TABLE [IF EXISTS] table_name;