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Pig, mail # user - avoiding Group by or filter


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Preeti Gupta 2013-03-04, 23:50
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Prashant Kommireddi 2013-03-05, 04:30
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Preeti Gupta 2013-03-05, 04:36
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Jonathan Coveney 2013-03-05, 11:14
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Preeti Gupta 2013-03-05, 15:10
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Eli Finkelshteyn 2013-03-05, 02:11
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Re: avoiding Group by or filter
Jonathan Coveney 2013-03-05, 22:06
There have been a number of explanations on the topic before, so I would
prefer to point at one of them (or ensure we document it better), but
basically all of the aggregation functions we use (sum, avg, etc) all
function on bags of stuff. This is actually true in SQL as well (it just
hides the "group all", but it is implied). In this case, you are grouping
all of the rows together in order to run the function on them, since you
cannot run a function on a relation, only on a bag. Does that make any
sense? I know this is sort of an annoying nuance to understand in Pig...
2013/3/5 Eli Finkelshteyn <[EMAIL PROTECTED]>

> Yes. You can use any eval function such as SUM or AVG as long as your data
> is in the format (item1, … , item, {(tup1), …(tupn)}). See
> http://pig.apache.org/docs/r0.10.0/func.html#eval-functions for more info.
>
> On Mar 4, 2013, at 3:50 PM, Preeti Gupta wrote:
>
> > Hello,
> >
> > Can I compute SUM or AVG without using GROUPBY OR FILTER?
>
>