Hive struct

[abhishek <ab...@gmail.com>]

hi all,

Please share your view on how can I do this

i have query in hive where one column is struct(1 to n strings),second column is string

i want to compare struct of first and last element with second column string, if first element matches i should get output first or last element matches with the second column then I should get last anything else should be null or 0


Example:

column 1 |  column 2 
<a,b,c,d>  |     a
<w,x,y,z>  |     z
<p,w,r,s>  |     w

I want to print this table as

column 1      |  column 2  | column 3
<a,b,c,d>      |     a               |     first
<w,x,y,z>      |     z                |     second
<p,w,r,s>      |     w               |      null or 0

Regards
Abhi

Re: Hive struct

[Stephen Sprague <sp...@gmail.com>]

ok.  i'll bite.

when you say "struct" do you mean that literally?  if so then you know the
first and last elements _by definition_. so that's easy and i presume you
can solve that.


other than that if you mean "map" or "array" i think you're not going to do
it in native hive.  For this I'd personally recommend looking at the
transform() function.  Its your back-door to do all sorts of wild and crazy
things that you can dream up.

That said there's not whole lot of collection functions i see listed in the
hive udf page. maybe some day those'll get a refresh.

keep in mind this is all my 2 cents only.  ymmv.


On Thu, May 2, 2013 at 9:28 PM, abhishek <ab...@gmail.com> wrote:

> hi all,
>
> Please share your view on how can I do this
>
> i have query in hive where one column is struct(1 to n strings),second
> column is string
>
> i want to compare struct of first and last element with second column
> string, if first element matches i should get output first or last element
> matches with the second column then I should get last anything else should
> be null or 0
>
>
> Example:
>
> column 1 |  column 2
> <a,b,c,d>  |     a
> <w,x,y,z>  |     z
> <p,w,r,s>  |     w
>
> I want to print this table as
>
> column 1      |  column 2  | column 3
> <a,b,c,d>      |     a               |     first
> <w,x,y,z>      |     z                |     second
> <p,w,r,s>      |     w               |      null or 0
>
> Regards
> Abhi