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Re: [NOVICE] Case Insensitive Searching?


  • From: Josh Berkus <josh(at)agliodbs(dot)com>
  • To: <bcschnei(at)attbi(dot)com>, <pgsql-novice(at)postgresql(dot)org>, <pgsql-php(at)postgresql(dot)org>
  • Subject: Re: [NOVICE] Case Insensitive Searching?
  • Date: Sun, 25 May 2003 12:58:54 -0700
  • Message-id: <200305251258.54689.josh@agliodbs.com> <text/plain>

Ben,

> So the question is, how do I perform a case insensitive search? Is there a
> DB setting I can set to ignore the case?

To the latter: No.

To the former, there are four ways that you can do a case-insensitive search 
in PostgreSQL:

1) Using ILIKE:    SELECT * FROM sometable WHERE textfield ILIKE 'value%';
2) Using Regexp operators (see Functions and Operators in the docs):
	SELECT * FROM sometable WHERE textfield ~* 'value';
3) Using UPPER() or LOWER() to change the case of the field before comparison; 
this approach can be better than 1) or 2) because these functions may be 
indexed, and thus if you are doing a "begins with" or "exact match" search 
your query may be indexed:
	SELECT * FROM sometable WHERE UPPER(textfield) LIKE (UPPER('value') || '%');
4) If most of your searches are "anywhere in field" searches on large text 
fields, I'd reccomend a look at the two "full text search" tools available in 
PostgreSQL, one in the /contrib of your source, the second from openFTS.org.

Overally, I would strongly recommend that you buy and read an introcductory 
PostgreSQL book before proceeding further with your project.

-- 
Josh Berkus
Aglio Database Solutions
San Francisco



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