Oracle Regex: Match Numbers Guide

Here is how you can use Oracle regular expressions to match numbers:

1. Match using the REGEXP_LIKE function,
   For example, to match an integer, you can use the following expression:
   SELECT column_name
   FROM table_name
   WHERE REGEXP_LIKE(column_name, ‘^[0-9]+$’);
2. This expression can match one or more numbers, and must only be numbers, without any other characters.
3. To extract numbers using the REGEXP_SUBSTR function, you can use the following expression:
   SELECT REGEXP_SUBSTR(column_name, ‘[0-9]+’)
   FROM table_name;
4. This expression can identify one or more numbers in a string and return the first one found.
5. Replace non-numeric characters using the REGEXP_REPLACE function. If you want to remove non-numeric characters from a string, you can use the following expression:
   SELECT REGEXP_REPLACE(column_name, ‘[^0-9]’, ‘’)
   FROM table_name;
6. This expression will replace all non-numeric characters and only keep numeric characters.

It is important to note that Oracle’s regular expressions are based on Perl-style regular expressions, which feature some special symbols and syntax. When using regular expressions, adjustments and expansions can be made according to specific needs.