事实证明，存在有效的内联"基于袋子的方法:

It turns out that there are "inline" bag-based approaches that work:

x = LOAD 'file:///a/b/c.csv' USING PigStorage() AS (a: int, b: int, c: int);
y = FOREACH x GENERATE a AS a: int, b AS b: int, c AS c: int, MAX(TOBAG(a, b, c)) AS g: int;