两种情况下不走map-reduce:
1. where ds >' ' //ds 是partition
2. select * from table //后面没有查询条件，什么都没有
1.建表
CREATE TABLE sal( id INT, name STRING, salary INT ) partitioned by (city string) ROW FORMAT DELIMITED FIELDS TERMINATED BY ' ' STORED AS TEXTFILE;
1.1 修改表及属性
#把id,name以外的列删除
alter table sal replace columns (id int, name string);
#增加列
alter table sal add columns (remark string);
#修改column
ALTER TABLE table_name
CHANGE col_old_name col_new_name
column_type;
ALTER TABLE sal CHANGE remark city string;2.导入数据
load data local inpath '/home/hadoop/in/mytable' overwrite into table sal; 1 zuansun 3000 none 2 zuansu2 4000 none 3 zuansu3 3000 none 4 zuansu4 4000 none 5 zuansu5 3000 none 6 zuansu6 4000 none 7 zuansu7 3000 none 8 zuansu8 4000 none 9 zuansu9 10000 none 10 zuansu10 20000 none 11 zuansu11 15000 none 12 zuansu12 25000 none
3.嵌套查询
from (select * from sal) e select e.id,e.name,e.salary where e.salary>3000;
#case when
select id,name,
case
when salary<10000 then '屌丝'
when salary>=10000 and salary<20000 then '中下等'
when salary>=20000 and salary<50000 then '高帅富'
else '外星人'
end as salarylevel
from sal;4.group by
select remark,sum(salary) from sal group by remark;
5.动态分区
5.1 创建临时表
CREATE TABLE sal_tmp( id INT, name STRING, salary INT, city string ) ROW FORMAT DELIMITED FIELDS TERMINATED BY ' ' STORED AS TEXTFILE;
5.2将数据导入到临时表中
load data local inpath '/home/hadoop/in/mytable' overwrite into table sal_tmp;
5.3 操作的配置
set hive.exec.dynamic.partition=true; // 允许动态分区 set hive.exec.dynamic.partition.mode=nonstrict; set hive.exec.dynamic.partitions.pernode=50000; set hive.exec.dynamic.partitions.partitions=50000; set hive.exec.max.created.files=500000; set mapred.reduce.tasks =20000; //每个任务默认的reduce数目 set hive.merge.mapfiles=true; //在Map-only的任务结束时合并小文件
5.4附partition相关参数：
hive.exec.dynamic.partition（缺省false）： 设置为true允许使用dynamic partitionhive.exec.dynamic.partition.mode（缺省strick）：设置dynamic partition模式（nostrict允许所有partition列都为dynamic partition，strict不允许）
hive.exec.max.dynamic.partitions.pernode （缺省100）：每一个mapreduce job允许创建的分区的最大数量，如果超过了这个数量就会报错
hive.exec.max.dynamic.partitions （缺省1000）：一个dml语句允许创建的所有分区的最大数量
hive.exec.max.created.files （缺省100000）：所有的mapreduce job允许创建的文件的最大数量
5.5
insert into table sal partition (city) select * from sal_tmp;
6. join操作
#建表 create table a(id int,gender string) row format delimited fields terminated by ' ' stored as textfile; #加载数据 load data local inpath '/home/hadoop/in/a' overwrite into table a; #内连接查询 select sal.id,sal.name,sal.salary,sal.city,a.gender from sal join a on(sal.id=a.id); #左外连接查询 select sal.id,sal.name,sal.salary,sal.city,a.gender from sal left outer join a on(sal.id=a.id);
7.创建索引
create index a_index on table a(id) AS 'org.apache.hadoop.hive.ql.index.compact.CompactIndexHandler' WITH DEFERRED REBUILD ;
8.桶
#临时表 create table tb_tmp(id int,age int, name string ,timeflag bigint) row format delimited fields terminated by ','; #带桶的表,4个桶 create table tb_stu(id int,age int, name string,timeflag bigint) clustered by (id) sorted by (age) into 4 buckets row format delimited fields terminated by ','; #加载数据到临时表 load data local inpath '/home/hadoop/in/tb_tmp' overwrite into table tb_tmp; 1,20,zxm,20140330 2,21,ljz,20140330 3,19,cds,20140330 4,18,mac,20140330 5,22,android,20140330 6,23,symbian,20140330 7,25,wp,20140330 8,20,cxd,20140330 9,21,fvd,20140330 10,19,cvb,20140330 11,18,erd,20140330 12,22,nid,20140330 13,23,fvd,20140330 14,19,cvb,20140330 15,18,e33,20140330 16,22,nid,20140330 #设置执行桶的属性 set hive.enforce.bucketing = true; #插入到tb_stu表 insert into table tb_stu select * from tb_tmp; #抽样 select * from tb_stu tablesample(bucket 1 out of 4 on id); 注：tablesample是抽样语句，语法：TABLESAMPLE(BUCKET x OUT OF y),相当于以下语句： SELECT * FROM numbersflat WHERE number % y = x-1;
9.RCfile
#rcfile 格式表 create table tb_rc(id int,age int, name string ,timeflag bigint) row format delimited fields terminated by ',' stored as rcfile; #插入数据,上表中已经有tb_tmp表，所以直接插入数据即可 insert into table tb_rc select * from tb_tmp;
10.分隔符的多样化（配合正则表达式使用）
#cat /tmp/liuxiaowen/1.txt 000377201207221125^^APPLE IPHONE 4S^^2 132288201210331629^^THINKING IN JAVA^^1 132288201210331629^^THIN ssss^^1111 132288201210331629^^THdd dd ddJAVA^^10 add jar /opt/app/hive-0.7.0-rc1/lib/hive-contrib-0.7.0.jar ; create external table tt(times string, product_name string, sale_num string ) ROW FORMAT SERDE 'org.apache.hadoop.hive.contrib.serde2.RegexSerDe' WITH SERDEPROPERTIES ( 'input.regex' = '([^^]*)\^\^([^^]*)\^\^([^^]*)', 'output.format.string' = '%1$s %2$s %3$s') STORED AS TEXTFILE; load data local inpath '/home/hadoop/in/tt' overwrite into table tt; hive> select product_name from tt; APPLE IPHONE 4S THINKING IN JAVA THIN ssss THdd dd ddJAVA
11.更加复杂的数据类型
11.1 array
cat login_array.txt 192.168.1.1,3105007010|3105007011|3105007012 192.168.1.2,3105007020|3105007021|3105007022 CREATE TABLE login_array ( ip STRING, uid array<BIGINT> ) PARTITIONED BY (dt STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' COLLECTION ITEMS TERMINATED BY '|' STORED AS TEXTFILE; 加载数据到hive表 LOAD DATA LOCAL INPATH '/home/hadoop/in/login_array' OVERWRITE INTO TABLE login_array PARTITION (dt='20130101'); #查看数据 select * from login_array; 192.168.1.1 [3105007010,3105007011,3105007012] 20130101 192.168.1.2 [3105007020,3105007021,3105007022] 20130101 select ip,uid[0] from login_array where dt='20130101'; --使用下标访问数组 192.168.1.1 3105007010 192.168.1.2 3105007020 select ip,size(uid) from login_array where dt='20130101'; #查看数组长度 192.168.1.1 3 192.168.1.2 3 select * from login_array where array_contains(uid,3105007010);#数组查找 192.168.1.1 [3105007010,3105007011,3105007012] 20130101
11.2 使用Map
cat map_test_raw:
2014-03-03 12:22:34#127.0.0.1#get#amap#src=123&code=456&cookie=789#status=success&time=2s
2014-03-03 11:22:34#127.0.0.1#get#autonavi#src=123&code=456#status=success&time=2s&cookie=789
#创建表
create external table map_test_raw(ts String,ip String,type String,logtype String,request Map<String,String>,response Map<String,String>)
ROW FORMAT DELIMITED FIELDS TERMINATED BY '#'
COLLECTION ITEMS TERMINATED BY '&'
MAP KEYS TERMINATED BY '='
stored as textfile;
LOAD DATA LOCAL INPATH '/home/hadoop/in/map_test_raw' OVERWRITE INTO TABLE map_test_raw;
#查看数据
select * from map_test_raw;
2014-03-03 12:22:34 127.0.0.1 get amap {"src":"123","code":"456","cookie":"789"} {"status":"success","time":"2s"}
2014-03-03 11:22:34 127.0.0.1 get autonavi {"src":"123","code":"456"} {"status":"success","time":"2s","cookie":"789"}11.3 使用struct
# cat login_struct.txt
192.168.1.1,zhangsan:40
192.168.1.1,lisi:41
192.168.1.1,gavin:42
192.168.1.1,wangwu:43
192.168.1.1,xiaoming:44
192.168.1.1,xiaojun:45
# 建表
CREATE TABLE login_struct (
ip STRING,
user struct<name:string,age:int>
)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY ','
COLLECTION ITEMS TERMINATED BY ':'
STORED AS TEXTFILE;
#导入数据
LOAD DATA LOCAL INPATH '/home/hadoop/in/login_struct' OVERWRITE INTO TABLE login_struct;
#查看数据
select ip,user from login_struct;
192.168.1.1 {"name":"zhangsan","age":40}
192.168.1.1 {"name":"lisi","age":41}
192.168.1.1 {"name":"gavin","age":42}
192.168.1.1 {"name":"wangwu","age":43}
192.168.1.1 {"name":"xiaoming","age":44}
192.168.1.1 {"name":"xiaojun","age":45}版权声明：本文为博主原创文章，未经博主允许不得转载。