查找数据中出现的前10位

Question

我正在尝试在我的twitter数据中找到前10位提及（@xxxxx）。我创建了初始表twitter.full_text_ts并将其加载到我的数据中。

create table twitter.full_text_ts as 
select id, cast(concat(substr(ts,1,10), ' ', substr(ts,12,8)) as timestamp) as ts, lat, lon, tweet 
from full_text; 

香港专业教育学院已经能够使用该查询（模式）

select id, ts, regexp_extract(lower(tweet), '(.*)@user_(\\S{8})([:| ])(.*)',2) as patterns 
from twitter.full_text_ts 
order by patterns desc 
limit 50; 

执行该提取提到在微博给了我

USER_a3ed4b5a 2010-03-07 03:46:23 fffed220 
USER_dc8cfa6f 2010-03-05 18:28:39 fffdabf9 
USER_dc8cfa6f 2010-03-05 18:32:55 fffdabf9 
USER_915e3f8c 2010-03-07 03:39:09 fffdabf9 
and so on... 

你可以看到fffed220等是提取模式。

现在我想要做的是计数每个这些提及（模式）发生的次数并输出前10位。例如，fffdabf9发生20次，fffxxxx发生17次等等。

Answer 1

最可读的方式做，这将是你的第一个查询保存到一个临时表，然后做临时表GROUPBY：

create table tmp as 
--your query 

select patterns, count(*) n_mentions 
from tmp 
group by patterns 
order by count(*) desc 
limit 10; 

Answer 2

with mentions as 
(select id, ts, 
regexp_extract(lower(tweet), '(.*)@user_(\\S{8})([:| ])(.*)',2) as patterns 
from twitter.full_text_ts 
order by patterns desc 
limit 50) 
select patterns, count(*) 
from mentions 
group by patterns 
order by count(*) desc 
limit 10;