Solved

regexp in SQL

Posted on 2006-07-12
2
720 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
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
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

PeopleSoft Has Never Been Easier

PeopleSoft Adoption Made Smooth & Simple!

On-The-Job Training Is made Intuitive & Easy With WalkMe's On-Screen Guidance Tool.  Claim Your Free WalkMe Account Now

Question has a verified solution.

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

Truncate is a DDL Command where as Delete is a DML Command. Both will delete data from table, but what is the difference between these below statements truncate table <table_name> ?? delete from <table_name> ?? The first command cannot be …
Note: this article covers simple compression. Oracle introduced in version 11g release 2 a new feature called Advanced Compression which is not covered here. General principle of Oracle compression Oracle compression is a way of reducing the d…
This video shows how to Export data from an Oracle database using the Datapump Export Utility.  The corresponding Datapump Import utility is also discussed and demonstrated.
Via a live example, show how to restore a database from backup after a simulated disk failure using RMAN.

738 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