One, de-duplicate hive table data

1. Copy the table structure

CREATE TABLE <new_table> LIKE <old_table>;

2. Insert the data after deduplication

insert overwrite table <new_table>(
select t.id, t.local_path
from (
select
id, local_path, row_number() over(distribute by id sort by local_path) as rn
from <old_table>
) t where t.rn=1
);

The structure is as follows

insert overwrite table <new_table> (
select <字段>
from (
select <字段>, row_number() over(distribute by <有重复的字段> sort by <重复字段的排列根据字段>) as rn
from <old_table>
) t where t.rn=1
);

You can also directly insert into the original table without creating a new table and update directly

3. De-duplication of partition table

#hive数据去重
      #获取表头
      fieldsTmp=$(hive -e "SET hive.cli.print.header=true;select * from ${dbname}.${table_name} limit 0;" | sed -e "s/\t/,/g;s/data\.//g" | grep -v "WARN")
      fields2=${fieldsTmp//,${table_name}.dt/}
      fields=${fields2//${table_name}./}
   hive -e "
   use $dbname;
   insert overwrite table $table_name partition(dt=$date_slice) select $fields from (select $fields,row_number() over(distribute by $tab_primarykey sort by $key_code desc)as rn from $table_name)t where t.rn=1"

The variables that need to be assigned in the sample code are as follows

${dbname}: database name

${table_name}: table name

${date_slice}: partition value

${tab_primarykey}: There are duplicate fields

${key_code}: The arrangement of repeated fields is based on the field

fields2=${fieldsTmp//, dt in ${table_name}.dt/} is your partition field

2. Take out the field name of the hive table in the script

#存储到文本
hive -e "SET hive.cli.print.header=true;select * from dbname.tablename limit 0;" | sed -e "s/\t/,/g;s/data\.//g" | grep -v "WARN" > fileds.csv

#赋值给变量
fields=$(hive -e "SET hive.cli.print.header=true;select * from dbname.tablename limit 0;" | sed -e "s/\t/,/g;s/data\.//g" | grep -v "WARN")

Get the field names of the hive table separated by commas

Three, save the hive query results to the local or hdfs

Save hive query results to local

hive -e "use test;insert overwrite local directory '/tmp/score' ROW FORMAT DELIMITED FIELDS TERMINATED BY',' select * from student"

To save to hdfs, you only need to remove local from the above command.

[Hive] Deduplicate table data, save hive query results locally or hdfs