Re: How to unnest an array with element indexes

Hello

Simple plpgsql function can helps

create or replace function unnest_rownum(anyarray)
returns table (id int, element anyelement) as $$
begin id := 1;
foreach element in array $1 loop
return next;
id := id + 1;
end loop;
return;
end $$ language plpgsql;

postgres=# select * from unnest_rownum(ARRAY[1,1,2,3,4,1,2,7]);
id | element
----+---------
1 | 1
2 | 1
3 | 2
4 | 3
5 | 4
6 | 1
7 | 2
8 | 7
(8 rows)

postgres=# select * from unnest_rownum(ARRAY['A','B','C']);
id | element
----+---------
1 | A
2 | B
3 | C
(3 rows)

Regards

Pavel

2014-02-19 20:57 GMT+01:00 AlexK <alkuzo(at)gmail(dot)com>:

> David,
>
> The array stores a time series of values for consecutive days. All I need
> is
> take an array such as ARRAY[1.1,1.2] and return to the client the following
>
> series_start_date + (array_index-1), array_value
>
> Based on what you are saying, the following should do it:
>
> with pivoted_array AS(
> select unnest(ARRAY[1.1,1.2])
> ),
> indexed_array AS(
> select
> row_number()OVER() AS element_index,
> unnest as element_value
> from pivoted_array)
> SELECT
> (DATE '2014-02-19' + INTERVAL '1d'*(element_index-1)) AS
> series_date,
> element_value AS series_value
> FROM indexed_array
>
> Can you confirm that this behavior is guaranteed and documented. I could
> not
> find it in the docs.
>
>
>
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