Order by generated column - sql

Question

I have following data structure:
CREATE TABLE test(
id INTEGER PRIMARY KEY,
data TEXT NOT NULL
);
INSERT INTO test (data) VALUES ('10.20.3.40'), ('10.100.3'), ('10.20.20.40')
The problem is that i need to order by data column using integer logic (dot-separated string as array of integers).
Using order by it returns data sorted as text:
SELECT data FROM test ORDER BY data
10.100.3
10.20.20.40
10.20.3.40
Result I need to achieve:
10.20.3.40
10.20.20.40
10.100.3
The simplest method to sort it properly without reimplementing arrays in SQLite which I've found is to add zero-padding to each part of data.
So basically I need to:
Select all data from table;
Split value of data column;
Add zero-padding and join it back;
Join newly generated column with reformatted data
Order by this column
What have I already done:
WITH RECURSIVE split_str(source, part) AS (
SELECT '10.20.3.40' || '.', NULL
UNION ALL
SELECT
substr(source, instr(source, '.') + 1),
substr('000000' || source, instr(source, '.'), 6)
FROM split_str WHERE source != ''
)
SELECT group_concat(part, '.') AS new_data FROM split_str WHERE part IS NOT NULL
It splits constant string '10.20.3.40' by dot, add leading zeros to each part and join it back using group_concat(). It returns:
000010.000020.000003.000040
Now I need to apply such a modification to values of data column from test table and somehow use this values for sorting. That's result I'm trying to get:
I'm not an expert in SQL (obviously) and don't understand how to apply expression in WITH clause on each data column separately.

Answer 1

As you can't use GROUP_CONCAT() if you want to preserve the order, just build up another string instead.
Then, only take the records where there's no more 'unpadded' string still to be processed.
WITH RECURSIVE
test_set(original)
AS
(
SELECT '10.20.3.40'
UNION ALL
SELECT '10.100.3'
UNION ALL
SELECT '10.20.20.40'
),
split_str(original, remaining, padded)
AS
(
SELECT original, original || '.', '' FROM test_set
---------
UNION ALL
---------
SELECT
original,
substr(remaining, instr(remaining, '.') + 1),
padded || '.' || substr('000000' || remaining, instr(remaining, '.'), 6)
FROM
split_str
WHERE
remaining != ''
)
SELECT
original,
padded
FROM
split_str
WHERE
remaining = ''
ORDER BY
padded
Demo: db<>fiddle.uk
(You may or may not want to strip the leading ., depending on your needs.)