Below is the hive table i have created:
CREATE EXTERNAL TABLE Activity (
column1 type, </br>
column2 type
)
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
LOCATION '/exttable/';
In my HDFS location /exttable, i have lot of CSV files and each CSV file also contain the header row. When i am doing select queries, the result contains the header row as well.
Is there any way in HIVE where we can ignore the header row or first line ?
If you are using Hive version 0.13.0 or higher you can specify "skip.header.line.count"="1" in your table properties to remove the header.
For detailed information on the patch see: https://issues.apache.org/jira/browse/HIVE-5795
you can now skip the header count in hive 0.13.0.
tblproperties ("skip.header.line.count"="1");
There is not. However, you can pre-process your files to skip the first row before loading into HDFS -
tail -n +2 withfirstrow.csv > withoutfirstrow.csv
Alternatively, you can build it into where clause in HIVE to ignore the first row.
If your hive version doesn't support tblproperties ("skip.header.line.count"="1"), you can use below unix command to ignore the first line (column header) and then put it in HDFS.
sed -n '2,$p' File_with_header.csv > File_with_No_header.csv
Lets say you want to load csv file like below located at /home/test/que.csv
1,TAP (PORTUGAL),AIRLINE
2,ANSA INTERNATIONAL,AUTO RENTAL
3,CARLTON HOTELS,HOTEL-MOTEL
Now, we need to create a location in HDFS that holds this data.
hadoop fs -put /home/test/que.csv /user/mcc
Next step is to create a table. There are two types of them to choose from. Refer this for choosing one.
Example for External Table.
create external table industry_
(
MCC string ,
MCC_Name string,
MCC_Group string
)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY ','
STORED AS TEXTFILE
LOCATION '/user/mcc/'
tblproperties ("skip.header.line.count"="1");
To remove the header from the csv file in place use:
sed -i 1d filename.csv
