外部表不返回其文件夹中的数据 [英] External table does not return the data in its folder

问题描述

我在 Hive 中在此位置创建了一个外部表:

I have created an external table in Hive with at this location :

CREATE EXTERNAL TABLE tb 
(
...
) 
PARTITIONED BY (datehour INT)
ROW FORMAT SERDE 'com.cloudera.hive.serde.JSONSerDe'
LOCATION '/user/cloudera/data';

数据存在于文件夹中，但是当我查询表时，它什么都不返回.表格的结构使其适合数据结构.

The data is present in the folder but when I query the table, it returns nothing. The table is structured in a way that it fits the data structure.

SELECT * FROM tb LIMIT 3;

Hive 表是否存在某种权限问题:特定用户是否有权查询某些表?您知道一些解决方案或变通方法吗?

Is there a kind of permission issue with Hive tables: do specific users have permissions to query some tables? Do you know some solutions or workarounds?

推荐答案

您已将表创建为基于 datehour 列的分区表，但是您正在放置数据在 /user/cloudera/data 中.Hive 将在 /user/cloudera/data/datehour=(some int value) 中查找数据.由于它是外部表配置单元不会更新元存储.你需要运行一些alter语句来更新

You have created your table as partitioned table base on column datehour, but you are putting your data in /user/cloudera/data. Hive will look for data in /user/cloudera/data/datehour=(some int value). Since it is an external table hive will not update the metastore. You need to run some alter statement to update that

这里是带分区的外部表的步骤:

So here are the steps for external tables with partition:

1.) 在您的外部位置 /user/cloudera/data 中，创建一个目录 datehour=0909201401

1.) In you external location /user/cloudera/data, create a directory datehour=0909201401

                                OR

加载数据使用:LOAD DATA [LOCAL] INPATH '/path/to/data/file' INTO TABLE partition(datehour=0909201401)

Load data using: LOAD DATA [LOCAL] INPATH '/path/to/data/file' INTO TABLE partition(datehour=0909201401)

2.) 创建表后，运行alter 语句:ALTER TABLE ADD PARTITION (datehour=0909201401)

2.) After creating your table run a alter statement: ALTER TABLE ADD PARTITION (datehour=0909201401)

希望它有帮助...!!!

Hope it helps...!!!

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