Order versions as numbers - sql

Question

I have a table with file-names and version with subversion of files separated by ..
FNAME, VERSION
A 0.0.10
B 10.12.412
-- For example
create table file_versions as
select chr(mod(level,13)+65) as fname
, decode(mod(level,99),0, '0',
mod(level,10)||'.'||mod(level,500)||'.'||mod(level,14)
)
as version
from dual connect by level < 1001;
I'd like to order files by version, but use versions as numbers
select fname, version from file_versions
order by fname, version
FNAME, VERSION
A 0.0.10
A 0.0.6
...
I'd like don't think about subversion level(there may be one number (0) or more(1.23.14123)). How should I write order by statement ?
I may write something like:
select fname, version from file_versions
order by fname
, to_number(substr(version, 1, instr(version, '.',1,1)-1))
, to_number(substr(version, instr(version, '.',1,1)+1, instr(version, '.',1,2)-instr(version, '.',1,1)-1))
, to_number(substr(version, instr(version, '.',1,2)+1))
But its not so good and will not work if one digit was added to the version string (e.g. 0.0.0.123). Is there a better solution?

Answer 1

You can use regexp_substr():
order by fname,
cast(regexp_substr(version, '[^.]+', 1, 1) as number),
cast(regexp_substr(version, '[^.]+', 1, 2) as number),
cast(regexp_substr(version, '[^.]+', 1, 3) as number)

Answer 2

You may use two regexp first for enhance you group to add 5 zeros to any group. And another one to take last 5 digits from each group. And you get constant length rows and be able to sort it as chars.
with s(txt) as (select '1' from dual
union all
select '1.12' from dual
union all
select '1.12.410' from dual
union all
select rpad('1.12.410',401,'.03') from dual
union all
select rpad('1.12.410',401,'.03')||'.01' from dual
union all
select rpad('1.12.410',401,'.03')||'.02' from dual
)
select txt,regexp_replace(regexp_replace(txt, '(\d+)','00000\1'),'\d+ (\d{5})','\1') from s
order by regexp_replace(regexp_replace(txt, '(\d+)','00000\1'),'\d+(\d{5})','\1')
It will work up to 99999 version or subversion.

Answer 3

More for fun than as a serious suggestion, here's an alternative to parsing the string -- treating the version numbers as inet addresses.
Trickier when you have three levels in your version, but trivial for four levels:
Starting with the idea of:
select a.i::varchar
from (select '192.168.100.128'::inet i union
select '22.168.100.128'::inet) a
order by 1;
i
--------------------
192.168.100.128/32
22.168.100.128/32
(2 rows)
So for three-level versions you can:
with
versions as (
select '1.12.1' v union
select '1.3.100'),
inets as (
select (v||'.0')::inet i
from versions)
select substr(i::varchar,1,length(i::varchar)-5)
from inets
order by i;
substr
---------
1.3.100
1.12.1
(2 rows)
Maybe everyone should have four level versions ...