Re: INDEX and LIKE - Mailing list pgsql-sql

From Olivier Hubaut
Subject Re: INDEX and LIKE
Date
Msg-id opsh8a6gzu94ope3@olivier.amaze.ulb.ac.be
Whole thread Raw
In response to INDEX and LIKE  (T E Schmitz <mailreg@numerixtechnology.de>)
List pgsql-sql
On Mon, 29 Nov 2004 12:19:12 +0000, T E Schmitz  
<mailreg@numerixtechnology.de> wrote:

> Hello,
>
> I need to be able to perform wildcard searches on a VARCHAR(100) column  
> of the form
>
> SELECT * FROM item WHERE serial_no LIKE '%12345678%'
>
> Would an index on serial_no do anything at all for this search?
>
No, It wouldn't. If you use "%" for the beginning of you search pattern, a  
seqential search is performed, ignoring the index wich use the beginning  
of the string in order to create it's B-tree.


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