I believe there is someone doing google summer of code on this very issue.
2011/8/16 唐亮 <leont...@gmail.com>
> Hi group,
> Can I use a nested group in foreach?
>
> For example:
>
> A = load data ... as (a1:..., a2:..., a3:..., ...)
> B = group A by a1;
>
> C = foreach B {
> * inner_group = group A by a2;*
> generate group, inner_group;
> }
>
> As the emphasized sentence,
> can I group the inner bag again from relation B?
>
> But the compiler complained 'group' is an invalid alias in 'inner_group' of
> relation C.
>
> So, can I or how can I use a nested group in foreach?
>
> Thanks!!
>
