Re: Array operator "sum array values" - Mailing list pgsql-general

From Pavel Stehule
Subject Re: Array operator "sum array values"
Date
Msg-id 162867790803310829q7990facdo4c02fd56a71c7b7d@mail.gmail.com
Whole thread Raw
In response to Array operator "sum array values"  (Scara Maccai <m_lists@yahoo.it>)
List pgsql-general
Hello

On 31/03/2008, Scara Maccai <m_lists@yahoo.it> wrote:
> Hi,
>
>  is there a syntax that sums the values of an array?
>
>  That is, having an array like
>
>  {1,3,8},{5,6,7}
>
>  something like
>
>  select arr[1:2][2:3]
>
>  gives
>
>  {1,3},{6,7}
>
>
>  ; what I'd like is:
>
>  select arr[1$2][2$3]
>
>  gives:
>
>  17 (that is, 1+3 + 6+7)
>
>  If there is no such operator, would it be complicated adding it to postgres?
>  I mean: is the "[:]" operator an internal thing (the parser "knows" about it) or is it just like any other operators
thatcan be added ? 
>
>

create or replace function sum_elements(anyarray)
returns anyelement as $$
select sum($1[i])
   from generate_series(array_lower($1,1),
                                       array_upper($1,1)) g(i);
$$ language sql immutable;

select sum_elements(array[1,2,3]); --> 6

Regards
Pavel Stehule
>
>
>
>
>
>
>
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