Subject | Re: [firebird-support] Re: can someone explain me |
---|---|
Author | Lester Caine |
Post date | 2009-06-24T08:22:08Z |
svanderclock wrote:
LIKE asks to check for any record LIKE the supplied filter. The fact
that IN THIS CASE the results could be filtered by the first letter of
the filter and could possibly then use the index selectively is just a
special case?
Personally I would be looking to either match the ID ( as in your first
case), or provide an additional filter to limit the number of records to
be compared. How does ID STARTING 'R' do in this case?
--
Lester Caine - G8HFL
-----------------------------
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk//
Firebird - http://www.firebirdsql.org/index.php
>> FROM GEO_PLACEI'm not sure that I would expect anything different?
>> WHERE
>> ID like 'R%'
>>
>> geo_place
>> indexed read: 542167
>> non indexed read: 0
LIKE asks to check for any record LIKE the supplied filter. The fact
that IN THIS CASE the results could be filtered by the first letter of
the filter and could possibly then use the index selectively is just a
special case?
Personally I would be looking to either match the ID ( as in your first
case), or provide an additional filter to limit the number of records to
be compared. How does ID STARTING 'R' do in this case?
--
Lester Caine - G8HFL
-----------------------------
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk//
Firebird - http://www.firebirdsql.org/index.php