因为您需要一个不同的分隔符，所以有一个更干净的解决方案

insert overwrite local directory '/tmp/mytable' 
row format delimited
fields terminated by ','
select * from mytable
;

语言手册

演示

Hive

create table mytable (i int,s string,d date);

insert into mytable values 
    (1,'hello','2017-03-01')
   ,(2,'world','2017-03-02')
;

select * from mytable
;

mytable.i   mytable.s   mytable.d
1   hello   2017-03-01
2   world   2017-03-02

insert overwrite local directory '/tmp/mytable' 
row format delimited
fields terminated by ','
select * from mytable
;

猛击

cat /tmp/mytable/*
1,hello,2017-03-01
2,world,2017-03-02

因为您的表是以文本格式存储的，所以您可以简单地使用get/getmerge将文件从hdfs复制到本地文件系统
得到
获取合并

演示

Hive

create table mytable (i int,s string,d date);

insert into mytable values 
    (1,'hello','2017-03-01')
   ,(2,'world','2017-03-02')
;

select * from mytable
;

mytable.i   mytable.s   mytable.d
1   hello   2017-03-01
2   world   2017-03-02

show create table mytable;

CREATE TABLE `mytable`(
  `i` int, 
  `s` string, 
  `d` date)
ROW FORMAT SERDE 
  'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe' 
STORED AS INPUTFORMAT 
  'org.apache.hadoop.mapred.TextInputFormat' 
OUTPUTFORMAT 
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  'hdfs://localhost:8020/user/hive/warehouse/mytable'
.
.
.

猛击

hdfs dfs -getmerge /user/hive/warehouse/mytable mytable.txt

cat mytable.txt 

1hello2017-03-01
2world2017-03-02

p、 在列之间有一个看不见的分隔符，字符soh，ascii值为1。

<mytable.txt tr $'\x01' ','
1,hello,2017-03-01
2,world,2017-03-02