Solved

regexp in SQL

Posted on 2006-07-12
2
716 Views
Last Modified: 2008-02-01
SELECT REGEXP_SUBSTR('Go to http://www.oracle.com/products and click on database',
'http://([[:alnum:]]+\.?){3,4}/?') RESULT
FROM dual;
Can some body explain what this is doing?
output : http://www.oracle.com/


What exactly +, \. , \n  do .
Thanks
0
Comment
Question by:avi_ny
2 Comments
 
LVL 19

Expert Comment

by:actonwang
ID: 17092052
>>http://([[:alnum:]]+\.?){3,4}/?

     it is a reg expression.

     it matches.
     http://  then 3 or 4 set of   alphanumeric charachters ending with . (\. because . is a special character) plus a '/' (optional because of ?).
0
 
LVL 23

Accepted Solution

by:
paquicuba earned 125 total points
ID: 17092634
>>> What exactly +, \. , \n  do .

+   Matches one or more occurrences of the preceding subexpression

\.  Escape Character:  Treat the subsequent metacharacter in the expression as a literal.
                                 Since "." ( dot ) has a special meaning within the context of a regular expression, you
                                 must use "\" (Escape Character) to treat "." (dot) as a literal.

\n  Backreference:  Matches the nth preceding subexpression, where n is an integer from 1 to 9.
 
 
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Why doesn't the Oracle optimizer use my index? Querying too much data Most Oracle developers know that an index is useful when you can use it to restrict your result set to a small number of the total rows in a table. So, the obvious side…
Working with Network Access Control Lists in Oracle 11g (part 1) Part 2: http://www.e-e.com/A_9074.html So, you upgraded to a shiny new 11g database and all of a sudden every program that used UTL_MAIL, UTL_SMTP, UTL_TCP, UTL_HTTP or any oth…
This video shows how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.
This video shows syntax for various backup options while discussing how the different basic backup types work.  It explains how to take full backups, incremental level 0 backups, incremental level 1 backups in both differential and cumulative mode a…

809 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question