java - 在hadoop生态系统中，我使用Pig并陷入以下查询中？

Question

country_landmass_sorted = foreach country_landmass {
country_landmass_count = foreach country generate group,COUNT(name) as r;
sorted  = ORDER country_landmass_count BY $1 DESC;
GENERATE group, sorted;
};

我收到以下错误。如何解决这个错误？

2016-03-25 22:19:33,519 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1200: Pig script failed to parse: 
<line 11, column 16> expression is not a project expression: (Name: ScalarExpression) Type: null Uid: null)
Details at logfile: /home/cloudera/pig_1458968172221.log

Answer 1

将其拆分，使用FOREACH生成计数，然后使用ORDER BY的正则表达式。试试这个。

A = LOAD 'file' USING PigStorage(',') as (a:chararray,b:int);
B = group A BY a;
C = FOREACH B GENERATE group,COUNT(A.a);
D = ORDER C By $1;