阿帕奇豬不同和計數

Question

我想弄清楚下面的問題。

有多少女性用戶提供了至少一個等級4.我認爲我的連接和過濾器是正確的，但我無法弄清楚計數部分已經嘗試了以下的衆多版本。

a = load '/user/pig/movie' AS (userid:int, movieid:int, rating:int, timestamp:chararray); 
b = load '/user/pig/reviewer' using PigStorage('|') AS (userid:int, age:int, gender:chararray, occupation:chararray, zip:chararray); 
a1 = filter a by rating == 4; 
b1 = filter b by gender == 'F'; 
c = join a1 by userid, b1 by userid; 
d = FOREACH c GENERATE COUNT(DISTINCT(userid)); 
dump d; 

Answer 1

你必須GROUP COUNT.Ref前：COUNT需要前一組全球計算所有聲明和GROUP BY語句組數。

d = GROUP c BY userid; 
e = FOREACH d GENERATE COUNT(DISTINCT(b1.userid)); 
dump e;