Hive学习笔记——DDL和DML基础语句

本文链接：https://blog.youkuaiyun.com/i000zheng/article/details/80680963

本文详细介绍了Hive中的DDL操作，包括创建简单表、外部表、分区表及Bucket表的方法，并演示了如何通过Hive进行表结构的修改，如添加列、更改表名、增加分区等。

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1. DDL 操作：数据定义语音

创建简单表

hive> CREATE TABLE pokes (foo INT, bar STRING);

创建外部表：

CREATE EXTERNAL TABLE page_view(viewTime INT, userid BIGINT,
     page_url STRING, referrer_url STRING,
     ip STRING COMMENT 'IP Address of the User',
     country STRING COMMENT 'country of origination')
COMMENT 'This is the staging page view table'
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\054'
STORED AS TEXTFILE
LOCATION '<hdfs_location>';

建分区表:

CREATE TABLE par_table(viewTime INT, userid BIGINT,
     page_url STRING, referrer_url STRING,
     ip STRING COMMENT 'IP Address of the User')
COMMENT 'This is the page view table'
PARTITIONED BY(date STRING, pos STRING)
ROW FORMAT DELIMITED ‘\t’
   FIELDS TERMINATED BY '\n'
STORED AS SEQUENCEFILE;

建Bucket表

CREATE TABLE par_table(viewTime INT, userid BIGINT,
     page_url STRING, referrer_url STRING,
     ip STRING COMMENT 'IP Address of the User')
COMMENT 'This is the page view table'
PARTITIONED BY(date STRING, pos STRING)
CLUSTERED BY(userid) SORTED BY(viewTime) INTO 32 BUCKETS
ROW FORMAT DELIMITED ‘\t’
   FIELDS TERMINATED BY '\n'
STORED AS SEQUENCEFILE;

创建表并创建索引字段dt：

其实分区字段就更改表名：是索引字段

hive> CREATE TABLE tablename (foo INT, bar STRING) PARTITIONED BY (dt STRING);

复制一个空表：

CREATE TABLE empty_key_value_store
LIKE key_value_store;

表添加一列：

hive> ALTER TABLE tablename ADD COLUMNS (new_col INT);

更改表名：

hive> ALTER TABLE oldname RENAME TO newname;

增加分区：

hive> ALTER TABLE table_name ADD [IF NOT EXISTS] partition_spec [ LOCATION 'location1' ] partition_spec [ LOCATION 'location2' ] ...
      partition_spec:
  : PARTITION (partition_col = partition_col_value, partition_col = partiton_col_value, ...)