SQL select max value of varchar

Question

I have a varchar column that contains data like '0 03-03-14', '1 04-03-14' and so on. I need to select the maximum one, in that case '1 04-03-14'.

My problem is that I can have the '1' (the max value) but how do I have to do if I also want the date ?

For now, I have this :

SELECT MAX(TO_NUMBER(SUBSTR(revision, 1, INSTR(revision, ' ')-1)))
    FROM table
    WHERE name = 'aname'
        AND t_name = 'tname'
    GROUP BY revision

Does anyone have an idea ?

Thanks

Answer 1

I assume you want something like max(version, date version), try this:

Select * from (
  Select * from (
    SELECT
        TO_NUMBER(SUBSTR(revision, 1, INSTR(revision, ' ')-1)) as rev
      , TO_DATE(SUBSTR(revision, 1, INSTR(revision, ' ')+1),'DD-MM-YY') as revDate
    FROM table
    WHERE name = 'aname'
    AND t_name = 'tname'
  ) extracted
  order by extracted.revDate, extracted.rev desc
) where rownum = 1

Answer 2

Do you mean this?

select max(revision)
from table
where name = 'aname' and t_name = 'tname';

It seems strange to put the revision number and date in one column. Is that really your data format? If not, modify your question with the actual data format.

Answer 3

Regarding your answers, I think the best solution would be to split those two parts :)