Re: [Q]: Indexes with LIKE clause

From: Paul Zola <pzola_at_us.oracle.com>
Date: 22 Nov 1994 15:04:55 GMT
Message-ID: <3at1an$t9b_at_dcsun4.us.oracle.com>

In article <James.Lawrence.17.000FF2D2_at_epamail.epa.gov> James.Lawrence_at_epamail.epa.gov (Lawrence James) writes:
}In article <39mjll$fni_at_s.ms.uky.edu> neil_at_ms.uky.edu (Neil Greene) writes:
}
}>What ill effects does the use of a LIKE clause have with respect to
}>index performance, if any??
 

}>-- Neil
}
}If the wildcard is in the front it will disable index usage, if it is on the
}back or middle the index will be used up to the wild card.
}
}Lawrence....

Also, if you use a bind variable (i.e. "where field like :1" ) you will also disable the index usage. This is because the parser does not know at parse time where the wild card will be in the bind variable.

---

Paul Zola                              pzola_at_oracle.com

Senior Technical Analyst -- Worldwide Technical Support Received on Tue Nov 22 1994 - 16:04:55 CET