Re: Index use for case insensitive query - Mailing list pgsql-novice

From Bruno Wolff III
Subject Re: Index use for case insensitive query
Date
Msg-id 20021001210550.GA27859@wolff.to
Whole thread Raw
In response to Index use for case insensitive query  (eric soroos <eric-psql@soroos.net>)
List pgsql-novice
On Tue, Oct 01, 2002 at 11:48:29 -0700,
  eric soroos <eric-psql@soroos.net> wrote:
> I've got a table where one of the main lookup access is by email address, which is generally a case insensitive
lookup. 
>
> With the constraints that: some of the entries aren't reall email addresses and I can't change the case of all the
databecause of that: 
>
> Is there a way to do a case insensitive index and appropriate query so that when searching for an email address, I
getthe benefit of an index? 

Yes you can make an index on a function.
You can do something like:
create index index_name on table_name (lower(column_name));

Then selects like the following should use an index:
select * from table_name where lower(column_name) = 'constant';

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