[Hive笔记]Hive常用命令整理

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Commonly used Hive Commands

DDL Commands

COMMAND	OBJECTS
CREATE	Database, Table
DROP	Database, Table
TRUNCATE	Table
ALTER	Database, Table
SHOW	Database, Tables, Table Properties, Partitions, Functions, Index
DESCRIBE	Database, Table, View

• Create database

hive> create database if not exist demoDB comment "This is a demo"
location '/user/hive/warehouse/demodb';

• Drop database

hive> drop database if not exist demoDB CASCADE;

• Describe database

hive>describe database extended demoDB;

• Show databases

hive> show databses;

• Use database

hive> use demoDB;

DML Commands

• LOAD

  LOAD DATA [LOCAL] INPATH 'filepath' [OVERWRITE] INTO TABLE [PARTITION (partcol1=val1, partcol2=val2...)]
  

  filepath 可以是：
  *相对路径， 例如 project/data1
  *绝对路径， 例如 /user/hive/project/data1
  *包含schema和authority的完整URL， 例如hdfs://namenode:9000/user/hive/project/data1

  filepath 可以用引用一个文件或者一个目录

  如果指定关键字LOCAL, 那么：

  • load命令将会从本地文件系统中查找文件路径
  • load命令将会拷贝所以文件到目标文件系统

  如果没有指定 LOCAL关键字，那么Hive将使用指定了的完整URL，或者使用以下规则：

  • 如未指定schema或authority， Hive将从记录了namenode URL的配置变量fs.default.name中获取
    *如果路径不是绝对路径，那么Hive将会默认关联/user/
    *Hive会将所有相关文件移动到目前表或分区下

• INSERT

  Standard Syntax

  INSERT OVERWRITE TBALE tablename1 [PARTITION (partcol1=val1,partcol2=val2) [IF NOT EXISTS]] select_statement1 FROM from_statement;
  INSERT INTO TABLE tablename1 [PARTITION (partcol1=val1,partcol2=val2)] select_statement1 FROM from_statement;
  

  Standard Syntax2

  INSERT INTO TABLE tablename [PARTITION (partcol1=val1, partcol2=val2)] VALUES values_row [, value_row ...];
  

• UPDATE
  Standard Syntax

   UPDATE tablename SET column = value [, col2 = val2 ] [WHERE expression];
  

• DELETE
  Standard Syntax

    DELETE FROM tablename [WHERE expression];
  

• MERGE

[未完待续]