Get even / odd / all numbers between two numbers

Question

I want to display all the numbers (even / odd / mixed) between two numbers (1-9; 2-10; 11-20) in one (or two) column.
Example initial data:

| rang  |              | r1 | r2 |
--------               -----|-----
| 1-9   |              | 1  | 9  |
| 2-10  |              | 2  | 10 |
| 11-20 |      or      | 11 | 20 |

CREATE TABLE initialtableone(rang TEXT);
INSERT INTO initialtableone(rang) VALUES
  ('1-9'),
  ('2-10'),
  ('11-20');

CREATE TABLE initialtabletwo(r1 NUMERIC, r2 NUMERIC);
INSERT INTO initialtabletwo(r1, r2) VALUES
  ('1', '9'),
  ('2', '10'),
  ('11', '20');

Result:

| output                         |
----------------------------------
| 1,3,5,7,9                      |
| 2,4,6,8,10                     |
| 11,12,13,14,15,16,17,18,19,20  |

Answer 1

Something like this:

create table ranges (range varchar);

insert into ranges 
values
('1-9'),
('2-10'),
('11-20');

with bounds as (
  select row_number() over (order by range) as rn,
         range,
         (regexp_split_to_array(range,'-'))[1]::int as start_value,
         (regexp_split_to_array(range,'-'))[2]::int as end_value
  from ranges
)
select rn, range, string_agg(i::text, ',' order by i.ordinality)
from bounds b
  cross join lateral generate_series(b.start_value, b.end_value) with ordinality i
group by rn, range

This outputs:

rn | range | string_agg                   
---+-------+------------------------------
 3 | 2-10  | 2,3,4,5,6,7,8,9,10           
 1 | 1-9   | 1,2,3,4,5,6,7,8,9            
 2 | 11-20 | 11,12,13,14,15,16,17,18,19,20