hive简单操作

创建表

CREATE TABLE u_data (  
    userid INT,  
    movieid INT,  
    rating INT,  
    unixtime STRING)  
    ROW FORMAT DELIMITED  
    FIELDS TERMINATED BY '\t'  
    STORED AS TEXTFILE;  

其中,hive支持的字段类型,并不多,可以简单的理解为数字类型和字符串类型,详细列表如下:

TINYINT  
SMALLINT  
INT  
BIGINT  
BOOLEAN  
FLOAT  
DOUBLE  
STRING  

添加分区

ALTER TABLE table_name ADD PARTITION (partCol = 'value1') location 'loc1'; //示例
ALTER TABLE table_name ADD IF NOT EXISTS PARTITION (dt='20130101') LOCATION '/user/hadoop/  warehouse/table_name/dt=20130101'; //一次添加一个分区

ALTER TABLE page_view ADD PARTITION (dt='2008-08-08', country='us') location '/path/to/us/part080808' PARTITION (dt='2008-08-09', country='us') location '/path/to/us/part080809';  //一次添加多个分区

删除分区

ALTER TABLE login DROP IF EXISTS PARTITION (dt='2008-08-08');

ALTER TABLE page_view DROP IF EXISTS PARTITION (dt='2008-08-08', country='us');

修改分区

ALTER TABLE table_name PARTITION (dt='2008-08-08') SET LOCATION "new location";
ALTER TABLE table_name PARTITION (dt='2008-08-08') RENAME TO PARTITION (dt='20080808');

添加列

ALTER TABLE table_name ADD COLUMNS (col_name STRING);  //在所有存在的列后面,但是在分区列之前添加一列

修改列

复制代码

CREATE TABLE test_change (a int, b int, c int);

// will change column a's name to a1
ALTER TABLE test_change CHANGE a a1 INT; 

// will change column a's name to a1, a's data type to string, and put it after column b.   The new table's structure is: b int, a1 string, c int
ALTER TABLE test_change CHANGE a a1 STRING AFTER b; 

// will change column b's name to b1, and put it as the first column. The new table's   structure is: b1 int, a string, c int
ALTER TABLE test_change CHANGE b b1 INT FIRST;

复制代码

修改表属性:

alter table table_name set TBLPROPERTIES ('EXTERNAL'='TRUE');  //内部表转外部表 
alter table table_name set TBLPROPERTIES ('EXTERNAL'='FALSE');  //外部表转内部表

表的重命名

ALTER TABLE table_name RENAME TO new_table_name

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