HIVE HSQL 基本操作命令

創建表：

　　hive>create table tablename(id int,name string,password string);

　　創建一個名字為tablename的表，表的屬性有int   id;  string   name;  string  password;

創建表時指定分隔符

　　hive> create table test1(name string,count int)row format delimited fields terminated by '/t';

加載表

　　hive> load data inpath '/user/hadoop/output7/part-r-00000' into table test1;

 

創建一個新表，結構與其他一樣
　　hive> create table table1 like table2;

　　創建一個表table1,表結構跟table2一樣;

 

創建分區表

　　hive> create table table1(id int,line string) partitioned by (dt string,country string);

顯示表里有多少條記錄(count 數大於50的有多少條記錄)

　　hive>select count(*) from tablename where count>50; 

排序用法order by (查詢count 數大於50並排序)

　　 select * from test2 where count > 50 order by count;

 

顯示表中有多少分區

　　hive> show partitions table1;

 

顯示所有表

　　hive> show tables;

 

顯示所有與u開頭的表

　　hive> show tables 'u*';

顯示表的結構信息

　　hive> describe test1;

 修改表名字

　　hive> alter table table1 rename to test3;

 在原表上新添加一列

　　hive> alter table test1 add columns(new_col2 int comment 'a commment');

　　hive> alter table test1 add columns(new_col3 int);

 刪除表

　　hive> drop table test3;

 從本地文件加載數據：
　　hive> LOAD DATA LOCAL INPATH '/home/hadoop/input/ncdc/micro-tab/sample.txt' OVERWRITE INTO TABLE records;

 加載分區表

　　hive> load data inpath '/user/hive/warehouse/clickstream_log/dt=2016-11-29/part-r-00000' overwrite into table clickstream_log PARTITION(dt = '2016-11-30');

 顯示所有函數

　　hive> show functions;

 查看函數的用法

　　hive> describe function substr;

 查看數組、map、結構
　　hive> select col1[0],col2['b'],col3.c from complex;

查看數組、map、結構
　　hive> select col1[0],col2['b'],col3.c from complex;


 內連接：
　　hive> SELECT sales.*, things.* FROM sales JOIN things ON (sales.id = things.id);

 查看hive為某個查詢使用多少個MapReduce作業
　　hive> Explain SELECT sales.*, things.* FROM sales JOIN things ON (sales.id = things.id);

 外連接：
　　hive> SELECT sales.*, things.* FROM sales LEFT OUTER JOIN things ON (sales.id = things.id);
　　hive> SELECT sales.*, things.* FROM sales RIGHT OUTER JOIN things ON (sales.id = things.id);
　　hive> SELECT sales.*, things.* FROM sales FULL OUTER JOIN things ON (sales.id = things.id);

 in查詢：Hive不支持，但可以使用LEFT SEMI JOIN
　　hive> SELECT * FROM things LEFT SEMI JOIN sales ON (sales.id = things.id);


 Map連接：Hive可以把較小的表放入每個Mapper的內存來執行連接操作
　　hive> SELECT /*+ MAPJOIN(things) */ sales.*, things.* FROM sales JOIN things ON (sales.id = things.id);

 INSERT OVERWRITE TABLE ..SELECT：新表預先存在
　　hive> FROM records2
    　　> INSERT OVERWRITE TABLE stations_by_year SELECT year, COUNT(DISTINCT station) GROUP BY year 
    　　> INSERT OVERWRITE TABLE records_by_year SELECT year, COUNT(1) GROUP BY year
    　　> INSERT OVERWRITE TABLE good_records_by_year SELECT year, COUNT(1) WHERE temperature != 9999 AND (quality = 0 OR quality = 1 OR quality = 4 OR quality = 5 OR quality = 9) GROUP BY year;  

 CREATE TABLE ... AS SELECT：新表表預先不存在
　　hive>CREATE TABLE target AS SELECT col1,col2 FROM source;

 創建視圖：
　　hive> CREATE VIEW valid_records AS SELECT * FROM records2 WHERE temperature !=9999;

 查看視圖詳細信息：
　　hive> DESCRIBE EXTENDED valid_records;

 

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傳統數據庫：
添加：

insert into 表名 values(); 
修改：

update 表名 set a=b where b=c; 
刪除：

delete from 表名where a=b;
查詢：

select * from 表名 where a=b;