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From: Sandeep Khurana <sandeep@infoworks.io>
Date: Tue, 20 Sep 2016 02:13:40 +0530
Message-ID: <CAL6T49VEW00vtGP0vOi=NPjNFr2i_Z35c54FL2x8hqDPsyh57w@mail.gmail.com>
Subject: Re: group by on varchar column
To: user@kylin.apache.org
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archived-at: Mon, 19 Sep 2016 20:43:46 -0000

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btw, we are using Kylin version 1.5.2

On Tue, Sep 20, 2016 at 2:03 AM, Sandeep Khurana <sandeep@infoworks.io>
wrote:

> Hello
>
> I have a query where i do group by on a varchar column. The column values
> are long sentences (not just single words). This column is part of a
> dimension table.
>
> When i select just from dimension table with this group by then I do
> get ~2000 records   .
>
> But when I join this dimension with the fact table and run the group by
> query then I get just 1 record as Kylin somehow assumes the VARCHAR column
> values as NULL. There is not even a single row which has value of this
> VARCHAR field as null.
>
> Same query I copy paste and run on the Hive tables, I do get more than
> thousand records.
>
> Strange thing is when I change the aggregate column to another VARCHAR
> column (city_name) whose values are just one word and run on kylin SQL
> editor then I do get proper records .
>
> 2 questions
>
> - Any idea why such behaviour ? Especially when Hive gives proper records
> whereas kylin returns just one record which has value of this big varchar
> field as NULL.
>
> - Is there any work around?
>
>

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<div dir=3D"ltr">btw, we are using Kylin version 1.5.2<div class=3D"gmail_e=
xtra"><br><div class=3D"gmail_quote">On Tue, Sep 20, 2016 at 2:03 AM, Sande=
ep Khurana <span dir=3D"ltr">&lt;<a href=3D"mailto:sandeep@infoworks.io" ta=
rget=3D"_blank">sandeep@infoworks.io</a>&gt;</span> wrote:<br><blockquote c=
lass=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;=
padding-left:1ex"><div dir=3D"ltr">Hello<div><br></div><div>I have a query =
where i do group by on a varchar column. The column values are long sentenc=
es (not just single words). This column is part of a dimension table.</div>=
<div><br></div><div>When i select just from dimension table with this group=
 by then I do get=C2=A0~2000=C2=A0records =C2=A0 .</div><div><br></div><div=
>But when I join this dimension with the fact table and run the group by qu=
ery then I get just 1 record as Kylin somehow assumes the VARCHAR column va=
lues as NULL. There is not even a single row which has value of this VARCHA=
R field as null.<br></div><div><div><br></div><div>Same query I copy paste =
and run on the Hive tables, I do get more than thousand records.</div><div>=
<br></div><div>Strange thing is when I change the aggregate column to anoth=
er VARCHAR column (city_name) whose values are just one word and run on kyl=
in SQL editor then I do get proper records .</div><div><br></div><div>2 que=
stions</div><div><br></div><div>- Any idea why such behaviour ? Especially =
when Hive gives proper records whereas kylin returns just one record which =
has value of this big varchar field as NULL.</div><div><br></div><div>- Is =
there any work around? =C2=A0</div><div><br></div>
</div></div>
</blockquote></div><br><div><br></div>
</div></div>

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