How determine if range list contains specified integer - sql

Question

Product type table contains product types. Some ids may missing :
create table artliik (liiginrlki char(3) primary key);
insert into artliik values('1');
insert into artliik values('3');
insert into artliik values('4');
...
insert into artliik values('999');
Property table contais comma separated list of types.
create table strings ( id char(100) primary key, kirjeldLku chr(200) );
insert into strings values ('item1', '1,4-5' );
insert into strings values ('item2', '1,2,3,6-9,23-44,45' );
Type can specified as single integer, e.q 1,2,3 or as range like 6-9 or 23-44
List can contain both of them.
How to all properties for given type.
Query
select id
from artliik
join strings on ','||trim(strings.kirjeldLku)||',' like '%,'||trim(artliik.liiginrlki)||',%'
returns date for single integer list only.
How to change join so that type ranges in list like 6-9 are also returned?
Eq. f list contains 6-9, Type 6,7,8 and 9 shoud included in report.
Postgres 13 is used.

Answer 1

I would suggest a helper function similar to unnest that honors ranges.
Corrected function
create or replace function unnest_ranges(s text)
returns setof text language sql immutable as
$$
with t(x) as (select unnest(string_to_array(s, ',')))
select generate_series
(
split_part(x, '-', 1)::int,
case when x ~ '-' then split_part(x, '-', 2)::int else x::int end,
1
)::text
from t;
$$;
Then you can 'normalize' table strings and join.
select *
from artliik a
join (select id, unnest_ranges(kirjeldLku) from strings) as t(id, v)
on a.liiginrlki = v;
The use of a function definition is of course optional. I prefer it because the function is generic and reusable.

Answer 2

dbfiddle.uk demo will only works on pg14, since only pg14 have multirange data type. But customizeable icu collation works in pg13.
Collation doc: https://www.postgresql.org/docs/current/collation.html
Idea: create a multirange text data type that will sort numeric value based on their numerical value. like 'A-21' < 'A-123'.
CREATE COLLATION testcoll_numeric (
provider = icu,
locale = '#colNumeric=yes'
);
CREATE TYPE textrange AS RANGE (
subtype = text,
multirange_type_name = mulitrange_of_text,
COLLATION = testcoll_numeric
);
So
SELECT
mulitrange_of_text (textrange ('1'::text, '11'::text)) #> '9'::text AS contain_9;
should return true.
artliik table structure remain the same, but strings table need to change a bit.
CREATE temp TABLE strings (
id text PRIMARY KEY,
kirjeldLku mulitrange_of_text
);
then query it:
SELECT DISTINCT
strings.id
FROM
artliik,
strings
WHERE
strings.kirjeldLku #> liiginrlki::text
ORDER BY
1;