Thread: [REPOST] plpgsql : looping over multidimensional array : getting NULL for subdimension
[REPOST] plpgsql : looping over multidimensional array : getting NULL for subdimension
From
Samba
Date:
Hi all,
I'm trying to loop over a multidimensional array and find if any of the elements in a sub-dimensional array are matching some known criteria but facing issue with NULL for the sub arrays.
I have a data structure that looks like:
some_array VARCHAR[][] := '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
I'm trying to assign the individual sub arrays to other array elements like:
other-array VARCHAR[];
other_array=some_array[1];
and I'm expecting to get '{samba,sarath,sreenivas}' for index 1 and {samba,mukhesh,pavan} for index 2;
however, I'm getting NULL.
Can some one explain the way I can assign subarrays to other array elements plpgsql?
Thanks and Regards,
Samba
PS;
Sorry for spamming but my earlier mail was having some issue with the Subject line because of resending stalled post.
I'm trying to loop over a multidimensional array and find if any of the elements in a sub-dimensional array are matching some known criteria but facing issue with NULL for the sub arrays.
I have a data structure that looks like:
some_array VARCHAR[][] := '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
I'm trying to assign the individual sub arrays to other array elements like:
other-array VARCHAR[];
other_array=some_array[1];
and I'm expecting to get '{samba,sarath,sreenivas}' for index 1 and {samba,mukhesh,pavan} for index 2;
however, I'm getting NULL.
Can some one explain the way I can assign subarrays to other array elements plpgsql?
Thanks and Regards,
Samba
PS;
Sorry for spamming but my earlier mail was having some issue with the Subject line because of resending stalled post.
Re: [REPOST] plpgsql : looping over multidimensional array : getting NULL for subdimension
From
Merlin Moncure
Date:
On Wed, Dec 1, 2010 at 10:51 AM, Samba <saasira@gmail.com> wrote:
> Hi all,
>
> I'm trying to loop over a multidimensional array and find if any of the
> elements in a sub-dimensional array are matching some known criteria but
> facing issue with NULL for the sub arrays.
>
> I have a data structure that looks like:
>
> some_array VARCHAR[][] :=
> '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
>
> I'm trying to assign the individual sub arrays to other array elements like:
>
> other-array VARCHAR[];
>
> other_array=some_array[1];
>
> and I'm expecting to get '{samba,sarath,sreenivas}' for index 1 and
> {samba,mukhesh,pavan} for index 2;
> however, I'm getting NULL.
>
> Can some one explain the way I can assign subarrays to other array elements
> plpgsql?
There is no truly effective way to do that. you can however slice the
array which is almost as good:
other_array=some_array[1:1];
note this will give {{samba,sarath,sreenivas}}, not {samba,sarath,sreenivas}
merlin
Re: [REPOST] plpgsql : looping over multidimensional array : getting NULL for subdimension
From
Samba
Date:
Thank you Merlin for your answer,
I tried that and is working as you said.
But when I do
other_array=some_array[1:2];
I'm getting the entire '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
not just the second subarray, i.e. '{{samba,mukhesh,pavan}}'.
Is there any way I can get only the corresponding slice of the array?
otherwise I need to call this function multiple times from my java client, once per each sub-array which I think will more expensive
that doing it in just one stored procedure call.
Regards,
Samba
I tried that and is working as you said.
But when I do
other_array=some_array[1:2];
I'm getting the entire '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
Is there any way I can get only the corresponding slice of the array?
otherwise I need to call this function multiple times from my java client, once per each sub-array which I think will more expensive
that doing it in just one stored procedure call.
Regards,
Samba
On Thu, Dec 2, 2010 at 2:04 AM, Merlin Moncure <mmoncure@gmail.com> wrote:
On Wed, Dec 1, 2010 at 10:51 AM, Samba <saasira@gmail.com> wrote:There is no truly effective way to do that. you can however slice the
> Hi all,
>
> I'm trying to loop over a multidimensional array and find if any of the
> elements in a sub-dimensional array are matching some known criteria but
> facing issue with NULL for the sub arrays.
>
> I have a data structure that looks like:
>
> some_array VARCHAR[][] :=
> '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
>
> I'm trying to assign the individual sub arrays to other array elements like:
>
> other-array VARCHAR[];
>
> other_array=some_array[1];
>
> and I'm expecting to get '{samba,sarath,sreenivas}' for index 1 and
> {samba,mukhesh,pavan} for index 2;
> however, I'm getting NULL.
>
> Can some one explain the way I can assign subarrays to other array elements
> plpgsql?
array which is almost as good:
other_array=some_array[1:1];
note this will give {{samba,sarath,sreenivas}}, not {samba,sarath,sreenivas}
merlin
Re: [REPOST] plpgsql : looping over multidimensional array : getting NULL for subdimension
From
Merlin Moncure
Date:
On Thu, Dec 2, 2010 at 9:03 AM, Samba <saasira@gmail.com> wrote:
> Thank you Merlin for your answer,
>
> I tried that and is working as you said.
> But when I do
> other_array=some_array[1:2];
> I'm getting the entire
> '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
>
> not just the second subarray, i.e. '{{samba,mukhesh,pavan}}'.
>
> Is there any way I can get only the corresponding slice of the array?
sure...some_array[2:2], etc
merlin
Re: [REPOST] plpgsql : looping over multidimensional array : getting NULL for subdimension
From
Merlin Moncure
Date:
On Thu, Dec 2, 2010 at 12:20 PM, Merlin Moncure <mmoncure@gmail.com> wrote:
> On Thu, Dec 2, 2010 at 9:03 AM, Samba <saasira@gmail.com> wrote:
>> Thank you Merlin for your answer,
>>
>> I tried that and is working as you said.
>> But when I do
>> other_array=some_array[1:2];
>> I'm getting the entire
>> '{{samba,sarath,sreenivas},{samba,mukhesh,pavan}}';
>>
>> not just the second subarray, i.e. '{{samba,mukhesh,pavan}}'.
>>
>> Is there any way I can get only the corresponding slice of the array?
>
> sure...some_array[2:2], etc
by the way, see:
http://archives.postgresql.org/pgsql-general/2010-04/msg01041.php (and
responses) for a more in depth treatment of the issue.
merlin