Postgres 14

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select version();

version

PostgreSQL 14.4 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-10), 64-bit

SELECT unnest as a from unnest(array[1,2]);

a

1

2

CREATE COLLATION numeric (provider = icu, locale = 'en@colNumeric=yes');
CREATE OR REPLACE FUNCTION array_sort (ANYARRAY)
RETURNS ANYARRAY LANGUAGE SQL
AS $$
with cte(a) as(
SELECT * from unnest($1))
select array_agg(a) from (select a from cte  ORDER BY a COLLATE "numeric"  NULLS LAST) as t;
$$;
SELECT
    array_sort (ARRAY (
            SELECT
                unnest(ARRAY['12'::text, '34'::text, '56'::text, '111'::text, 'NULL'])
        EXCEPT
        SELECT
            unnest(ARRAY['AA', 'cc', 'P4', 'G8']))) AS modifiers;

modifiers

{12,34,56,111,"NULL"}

with cte(a)
as 
(
(select
       unnest(array['12'::text, '34'::text, '56'::text,'111'::text, 'NULL']) as a)
except 
(select unnest(array['AA', 'cc', 'P4', 'G8'])))
select * from cte order by a COLLATE "numeric";

a

12

34

56

111

NULL

select 'a 111' <  'b 56' COLLATE "numeric" as true;

true

t