-- split into 2 datasets
SPLIT Input_data INTO A IF Field > 0, B if Field <= 0;

-- count > 0 records
A_grp = GROUP A ALL;
A_count = FOREACH A_grp GENERATE COUNT(A);

-- count <= 0 records
B_grp = GROUP B ALL;
B_count = FOREACH B_grp GENERATE COUNT(B);

希望这会有帮助！！