Hive import csv file example

Table of contents

• text
  • First create the table
  • Import data and query
  • other considerations
  • Summarize

text

The existing file is in csv format and needs to be imported into hive. Set the content of csv as follows

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1001,zs,23
1002,lis,24

First create the table

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create table if not exists csv2(
    uid int,
    uname string,
    age int
)
row format serde 'org.apache.hadoop.hive.serde2.OpenCSVSerde'
stored as textfile ;

Import data and query

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load data local inpath '/data/csv2.csv' into table csv2;
select * from csv2;

other considerations

If the created table is in parquet format, can it load and import csv file?

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drop table csv2;
create table if not exists csv2(
    uid int,
    uname string,
    age int
)
row format serde 'org.apache.hadoop.hive.serde2.OpenCSVSerde'
stored as parquet ;

load data local inpath '/data/csv2.csv' into table csv2;
select * from csv2;

An error will be reported when using

Failed with exception java.io.IOException:java.lang.RuntimeException: hdfs://192.168.10.101:8020/user/hive/warehouse/csv2/csv2.csv is not a Parquet file. expected magic number at tail [80, 65, 82, 49] but found [44, 50, 52, 10]

**No, you need to import it into textfile first, and then import it into parquet from the temporary table,** as follows

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drop table csv2;
create table if not exists csv2
(
    uid   int,
    uname string,
    age   int
)
    row format serde 'org.apache.hadoop.hive.serde2.OpenCSVSerde'
    stored as textfile;
-- 先导入csv文件到表格csv2,保存格式是textfile
load data local inpath '/data/csv2.csv' into table csv2;


drop table csv3;
-- 创建csv3,保存格式parquet
create table if not exists csv3
(
    uid   int,
    uname string,
    age   int
)
    row format delimited
        fields terminated by ','
    stored as parquet;
-- 提取csv2的数据插入到csv3
insert overwrite table csv3 select * from csv2;

Summarize

• The key is to introduce org.apache.hadoop.hive.serde2.OpenCSVSerde
• csvTo save to hive, parquetyou need to save astextfile