Re: Custom sort order with jsonb key

On Thu, Jun 23, 2016 at 2:38 PM, Anton Ananich <anton.ananich@gmail.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.