Re: Custom sort order with jsonb key

On Thu, Jun 23, 2016 at 2:38 PM, Anton Ananich <anton(dot)ananich(at)gmail(dot)com>
wrote:

> Dear colleagues,
>
> I have a table in PostgreSQL with some data:
>
> create table FOO (
> key jsonb
> );
>
> insert into FOO(key) values ('[2014]');
> insert into FOO(key) values ('[2015]');
> insert into FOO(key) values ('[2016]');
> insert into FOO(key) values ('[2014, 2]');
> insert into FOO(key) values ('[2014, 2, 3]');
> insert into FOO(key) values ('[2014, 3]');
> insert into FOO(key) values ('[2014,2,4]');
> insert into FOO(key) values ('[2014, 2,4]');
> insert into FOO(key) values ('[2014,3,13]');
> insert into FOO(key) values ('[2014, 2, 15]');
>
> And I try to sort these rows like that:
>
> SELECT key FROM FOO order by key;
>
> The result is:
>
> [2014]
> [2015] <==
> [2016] <==
> [2014, 2]
> [2014, 3] <==
> [2014, 2, 3]
> [2014, 2, 4]
> [2014, 2, 4]
> [2014, 2, 15]
> [2014, 3, 13]
>
> But what I need is
>
> [2014]
> [2014, 2]
> [2014, 2, 3]
> [2014, 2, 4]
> [2014, 2, 4]
> [2014, 2, 15]
> [2014, 3] <==
> [2014, 3, 13]
> [2015] <==
> [2016] <==
>
> is there a way to achieve it?
>

​Maybe try:

ORDER BY key->>1::int​, key->>2::int, key->>3::int

There is no easy way, presently, to convert from a json array to a
PostgreSQL array. If you do that I believe that those sort based upon the
values and not lexically.

SELECT *
FROM ( VALUES (ARRAY[2014]::int[], ARRAY[2014,2]::int[],
ARRAY[2015]::int[]) ) vals (v)
ORDER BY v;

David J.