Re: Cast json array to postgres array and preserve order of elements

From: Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com>
To: otar shavadze <oshavadze(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Cast json array to postgres array and preserve order of elements
Date: 2020-05-10 15:07:58
Message-ID: 70e3c24d-317a-5469-426e-c8b8da91ab72@2ndQuadrant.com
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On 5/10/20 8:21 AM, otar shavadze wrote:
> When I want t to convert json array into postgres array, I do:
>
> with t(j) as(
>     select '{"my_arr":[3,1,2]}'::json
> )
> SELECT ARRAY(SELECT json_array_elements_text(j->'my_arr')) from t
>
>
> It works like a charm and I never noticed any problem, but I'm asking
> here just to make sure,  order of elements will be preserved always? 
> Is that guaranteed in above example, or not?
>
>

yes. The order is significant and the elements are produced in array order.

cheers

andrew

--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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