How to extract only numbered rows from a column

Question

For e.g: I have a column named "Card No", its a varchar but majority of the rows contain numbers and few contains alphanumeric numbers. I want to ignore all the records that are not numbers.

Below are a few examples for the same:

Select CardNo from XX;

Result:

CardNo:
_______
1234,
5467,
1234/5467,
abc 667,
efg428

In the above result set, I want to eliminate the last three values. Please advise.

Answer 1

Select CardNo from XX where isNumeric(CardNo) = 1

Answer 2

Oracle 10+ has a regular expression system that you could use. Just so you know, no indexes can or will be used for this type of comparison. Oracle will need to look at every single row.

Take a look at http://docs.oracle.com/cd/B12037_01/server.101/b10759/functions114.htm#SQLRF06300

Something like:

WHERE REGEXP_INSTR('CardNo', '[^0-9]+') > 0

Answer 3

Using regular expressions is probably the best choice here, but if you don't feel like going that route you could do something like this:

select CLEANED_CARDNO
  from (select CARDNO CLEANED_CARDNO,
               replace(TRANSLATE(CARDNO, '0123456789/', '~'), '~', null) STATUS
          from (select CARDNO from XX))
 where STATUS is null;

Changing the second argument in the TRANSLATE() function will allow you to include whatever characters you want.

Answer 4

Select CardNo from XX
where translate(CardNo, ' 0123456789', ' ') is null