Hive lateral view使用

多行转换:lateral view

说明:lateral view用于和json_tuple,parse_url_tuple,split, explode等UDTF一起使用,它能够将一行数据拆成多行数据,在此基础上可以对拆分后的数据进行聚合。

hive> select s.x,sp from test.dual s lateral view explode(split(concat_ws(',','1','2','3','4','5','6','7','8','9'),',')) t as sp;
x sp
a 1
b 2
a 3

解释一下,from后面是你的表名,在表名后面加lateral view explode。。。(你的行转列sql) ,还必须要起一个别名,我这个字段的别名为sp。然后再看看select后面的 s.*,就是原表的字段,我这里面只有一个字段,且为X

SELECT * FROM exampleTable LATERAL VIEW explode(col1) myTable1 AS myCol1 LATERAL VIEW explode(myCol1) myTable2 AS myCol2;

抽取一行数据转换到新表的多列样例:
http_referer是获取的带参数请求路径,其中非法字符用\做了转义,根据路径解析出地址,查询条件等存入新表中,

drop table if exists t_ods_tmp_referurl;
create table t_ ods _tmp_referurl as
SELECT a.*,b.*
FROM ods_origin_weblog a LATERAL VIEW parse_url_tuple(regexp_replace(http_referer, "\"", ""), 'HOST', 'PATH','QUERY', 'QUERY:id') b as host, path, query, query_id; 

复制表,并将时间截取到日:

drop table if exists t_ods_tmp_detail;
create table t_ods_tmp_detail as 
select b.*,substring(time_local,0,10) as daystr,
substring(time_local,11) as tmstr,
substring(time_local,5,2) as month,
substring(time_local,8,2) as day,
substring(time_local,11,2) as hour
From t_ ods _tmp_referurl b;

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