sql - 优雅的 HiveQL 查询

Question

我有一个像这样行的文件:

232404812.913232|1248|ip:tcp:jxta
232404812.913238|66|ip:udp:data
232404812.913615|98|ip:udp:l2tp:ppp:ip:tcp

我执行了以下 HiveQL 命令:

CREATE EXTERNAL TABLE b_packet (timestamp string, packet_length int, protocol string) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY "|" 
LOCATION 's3://b-file/input/'; 

CREATE EXTERNAL TABLE b_packet_out (protocol string, cnt int) 
ROW FORMAT DELIMITED FIELDS TERMINATED BY "\t" 
LOCATION 's3://b-file/output/1/'; 

INSERT OVERWRITE TABLE b_packet_out SELECT 'overall', 
COUNT(*) FROM b_packet GROUP BY protocol; 

INSERT INTO TABLE b_packet_out SELECT 'tcp', 
COUNT(*) FROM b_packet WHERE protocol REGEXP '^ip:tcp'; 

INSERT INTO TABLE b_packet_out SELECT 'udp', 
COUNT(*) FROM b_packet WHERE protocol REGEXP '^ip:udp'; 

INSERT INTO TABLE b_packet_out SELECT 'icmp', 
COUNT(*) FROM b_packet WHERE protocol REGEXP '^ip:icmp'; 

这样我在输出表中有以下内容。

hive> select * from b_packet_out;
OK
udp 2241
overall 10000
icmp    64
tcp 7633

HiveQL 查询是否有更优雅的方式，以便我可以减少行数以获得相同的输出？

Answer 1

select 
count(*) as overall,
sum( if(protocol like '^ip:tcp',1,0) as tcp,
sum( if(protocol like '^ip:udp',1.0) as udp,
sum( if(protocol like '^ip:icmp'1,0) as icmp 
from b_packet  

这会在一次数据传递中生成相同的计数。

如果你有更多的协议(protocol)，你也可以说
选择
拆分(协议(protocol)，':')[1]，
数数(*)
按拆分分组(协议(protocol)，':')[1]
但这不会给出总体计数。