Re: use of LIKE '%TARGET' vs = 'TARGET'

From: <ronb_at_digitalmarket.com>
Date: Mon, 17 Aug 1998 22:04:59 GMT
Message-ID: <6ra9eb$p49$1@nnrp1.dejanews.com>

if you do 'where column_name LIKE '%TARGET' Oracle can not use the index (if you have one) on column_name. This is because if the leading characters are not provided (i.e. using the wildcard % as the first character of a LIKE search) there is no way the hashing algorithm can work, so Oracle must do a full table scan, and that is what take so long.

Ron Bogdnoff

In article <6ra10d$bs1$1_at_nnrp1.dejanews.com>, chrisoc_at_ans.net wrote:
>
>
> Even when the result set is the same, LIKE is a real performance
> hog. Does anybody know exactly what it is doing, that takes all the
> time?
>
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-----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum Received on Mon Aug 17 1998 - 17:04:59 CDT