使用SUM（）时Pig Script错误

Question

运行此PIG脚本时出现以下错误....请帮助!!! 提前谢谢。

"ERROR 1000: Error during parsing. Scalars can be only used with projections"

MOVIES = LOAD '/MOVIES' using PigStorage(',') as (mid:double, mn:chararray, yr:int, rt:float, dr:int);

Filter11 = filter MOVIES by $2 >= 1950;

Filter12 = filter Filter11 by $2 <= 1960;

Group1 = group Filter12 by yr;

Count1 = foreach Group1 generate group, COUNT(Filter12);

Sum1 = foreach Count1 generate SUM(Group1);

DUMP Sum1;

Answer 1

结合两个过滤条件，在最后一步中，将计数总和，即COUNT（Filter11）或$ 1。

MOVIES = LOAD '/MOVIES' using PigStorage(',') as (mid:double, mn:chararray, yr:int, rt:float, dr:int);
Filter11 = filter MOVIES by ($2 >= 1950 and $2 <= 1960);
Group1 = group Filter11 by yr;
Count1 = foreach Group1 generate group, COUNT(Filter11);
Sum1 = foreach Count1 generate SUM($1);
DUMP Sum1;