访问 pig 中的模式值

Question

数据集 - 包含 PostId 和用户 ID

20    1
21    2
45    3
85    1
48    1
98    1
74    1
96    2
63    2
33    3
44    3
55    3
66    3
77    3

我想访问最大没有的userID。共 post

猪码

A = load '/home/cloudera/Desktop/post.txt' as (postid:chararray, userid:chararray);

B = load '/home/cloudera/Desktop/user.txt' as (name:chararray, id:chararray);

C = group A by userid;

D = foreach C generate group,COUNT(A.postid) as count;

E = order D by count DESC;

F = limit D 1;

它给出输出 -

(3,6)

现在执行 F 语句后，从 user.txt 访问与 A.userid 相同的用户名的 PIG 语句应该是什么？

Answer 1

使用下面的 SQL 语句获得所需的输出

declare @var int = (select max(cn) from (select count(post) cn from temp group by userid) c)    
select * from (select userid,count(post) as pso from temp group by userid ) as c where pso = @var

Answer 2

添加另一个语句以从关系 F

中获取第一列

G = FOREACH F GENERATE [=10=];
DUMP G;