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Pig, mail # user - how to perform GROUP BY in PIG for this case:


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Re: how to perform GROUP BY in PIG for this case:
Russell Jurney 2012-09-29, 23:15
answer = foreach (group data by ISOToMonth(Date)) generate group as
month, MAX(data.rate) as max_rate;

Note, you will need your date in ISO8601 format, and you can use
CustomFormatToISO to convert it if it's is a string, or UnixToISO if
your date is a long.

See:

http://pig.apache.org/docs/r0.10.0/api/org/apache/pig/piggybank/evaluation/datetime/convert/CustomFormatToISO.html
http://pig.apache.org/docs/r0.10.0/api/org/apache/pig/piggybank/evaluation/datetime/convert/UnixToISO.html
http://pig.apache.org/docs/r0.10.0/api/org/apache/pig/piggybank/evaluation/datetime/truncate/ISOToMonth.html

Russell Jurney http://datasyndrome.com

On Sep 29, 2012, at 3:02 PM, yogesh dhari <[EMAIL PROTECTED]> wrote:

>
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> Hi all,
>
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> I have this data, having fields  (Date, symbol, rate)
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> and I want it to be group by Months, and to find out the maximum rate value for each month.
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> like: for month (08, 36.3), (09, 36.4), (10, 36.8), (11, 37.5) ..
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>
> (2009-08-21,CLI,33.38)
>
> (2009-08-24,CLI,33.03)
>
> (2009-08-25,CLI,33.16)
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> (2009-08-26,CLI,32.78)
>
> (2009-08-27,CLI,32.79)
>
> (2009-08-28,CLI,33.37)
>
> (2009-08-31,CLI,32.51)
>
> (2009-09-11,CLI,34.08)
>
> (2009-09-14,CLI,35.19)
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> (2009-09-15,CLI,35.82)
>
> (2009-09-16,CLI,36.58)
>
> (2009-09-24,CLI,33.98)
>
> (2009-09-25,CLI,32.44)
>
> (2009-09-28,CLI,33.34)
>
> (2009-09-29,CLI,33.6)
>
> (2009-09-30,CLI,33.24)
>
> (2009-10-01,CLI,31.98)
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> (2009-10-02,CLI,31.21)
>
> (2009-10-05,CLI,31.31)
>
> (2009-10-21,CLI,32.86)
>
> (2009-10-26,CLI,33.15)
>
> (2009-10-27,CLI,32.71)
>
> (2009-10-28,CLI,32.03)
>
> (2009-10-29,CLI,32.05)
>
> (2009-10-30,CLI,31.88)
>
> (2009-11-02,CLI,31.88)
>
> (2009-11-03,CLI,31.16)
>
> (2009-11-04,CLI,31.47)
>
> (2009-11-09,CLI,31.59)
>
> (2009-11-25,CLI,30.58)
>
> (2009-11-27,CLI,30.19)
>
> (2009-11-30,CLI,30.86)
>
> (2009-12-01,CLI,31.74)
>
> (2009-12-02,CLI,32.62)
>
> (2009-12-03,CLI,33.43)
>
> (2009-12-04,CLI,34.12)
>
> (2009-12-07,CLI,33.77)
>
> (2009-12-08,CLI,33.8)
>
> (2009-12-09,CLI,33.71)
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>
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> Please help and suggest .
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>
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> Thanks & Regards
>
> Yogesh Kumar
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>