HQL操作日常使用命令總結

建表

create table mydb.userinfo(name string,addressi string)
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '\t'
LINES TERMINATED BY '\n'
STORED AS TEXTFILE;

創建分區表

CREATE TABLE mydb.userinfo    --創建表
(col1 string, col2 date, col3 double), 
partitioned by (datekey date),  --可以多個字段的組合分區 
ROW FORMAT DELIMITED 
FIELDS TERMINATED BY ',' 
Stored AS TEXTFILE;

數據導入到表mydb.userinfo中

load data local inpath "/home/dahaizi/data/userinfo.txt" 
overwrite into table mydb.userinfo;

向表中插入數據

insert into table(col1,col2,col3) values('a','b','c')

將查詢的數據插入到已有的表中

INSERT INTO TABLE table_Name
PARTITION (DateKey),
SELECT col1,col2,col3,DateKey FROM otherTable
WHERE DATEKEY IN ('2017-02-26','2013-06-12','2013-09-24'),
GROUP BY col1,col2,col3,DateKey
DISTRIBUTE BY DateKey

將查詢的數據存儲的hdfs目錄中

insert overwrite directory '/jc_bdcqs/qsy'
row format delimited
fields terminated by ','
select * from zqs_gs_g60_0730_list;
!quit

HQL查詢常用設置項

1）設置計算容錯率（防止因計算過程出錯而異常退出程序）:
set mapred.max.map.failures.percent=100;
2）限制查詢輸出文件的個數
set mapred.reduce.tasks=1;
3） 控制最大reduce的數量，不會影響mapred.reduce.tasks的設置
set hive.exec.reducers.max = 100;
4） 一個job會有多少個reducer來處理，默認爲1G
set hive.exec.reducers.bytes.per.reducer = 1000000000;

設置動態分區

set hive.exec.dynamic.partition=true;(可通過這個語句查看：set hive.exec.dynamic.partition;), 
set hive.exec.dynamic.partition.mode=nonstrict; 
SET hive.exec.max.dynamic.partitions=100000;(如果自動分區數大於這個參數，將會報錯),
SET hive.exec.max.dynamic.partitions.pernode=100000;

刪除表

drop table tb_name;
或清空表
truncate table table_name;

刪除分區

ALTER TABLE table_Name DROP PARTITION (Datekey='20190606');

新增分區

alter table tb_name add partition (Datekey = ‘20190606’);