首先認識什么是分區
Hive 中的分區就是分目錄，把一個大的數據集根據業務需要分割成更下的數據集。
1. 如何定義分區，創建分區
hive> create table test(name string,sex int) partitioned by (birth string, age string);
Time taken: 0.044 seconds
hive> alter table test add partition (birth='1980', age ='30');
Time taken: 0.079 seconds
hive> alter table test add partition (birth='1981', age ='29');
Time taken: 0.052 seconds
hive> alter table test add partition (birth='1982', age ='28');
Time taken: 0.056 seconds
hive> show partitions test;
birth=1980/age =30
birth=1981/age =29
birth=1982/age =28
2. 如何刪除分區
hive> alter table test drop partition (birth='1980',age='30');
3. 加載數據到指定分區
load data local inpath '/home/hadoop/data.log' overwrite into table
test partition(birth='1980-01-01',age='30');
創建分區原則： 最少粒度原則
4 向partition_test的分區中插入數據：
hive> insert overwrite table partition_test partition(stat_date='20110728',province='henan') select member_id,name from partition_test_input where stat_date='20110728' and province='henan';
5 還可以同時向多個分區插入數據，0.7版本以后不存在的分區會自動創建，0.6之前的版本官方文檔上說必須要預先創建好分區：
hive>
> from partition_test_input
> insert overwrite table partition_test partition (stat_date='20110526',province='liaoning')
> select member_id,name where stat_date='20110526' and province='liaoning'
> insert overwrite table partition_test partition (stat_date='20110728',province='sichuan')
> select member_id,name where stat_date='20110728' and province='sichuan'
> insert overwrite table partition_test partition (stat_date='20110728',province='heilongjiang')
> select member_id,name where stat_date='20110728' and province='heilongjiang';
Total MapReduce jobs = 4