Re: Better way to test if exist

From: "Obnoxio The Clown" <obnoxio@hotmail.com> > >From: Dirk Niemeier <dirk.niemeier@stueken.de> >>what is the best way to test if an duplicate value exist ? >>Example: A indexed table column char(3) with 4 different entries. But >>this 4 entries are duplicate average 1000 times. >> >>Now I tried to test like this: >> >>select distinct test_column from test_table where <column_test> = 'XXX';>> >>That works fine, but it's very slow when the entry exists. Isn't there a >>better way ? I tried this on 100 million rows with a spread of 32768 values and found no perceptible difference in performance. However, even given that my server is undergoing crucifixion by data load, I still got response times of around 1 - 1.5 seconds (most of which involved getting dbaccess to start.) What do you mean by slow? >I haven't tested it, but how about: >select FIRST 1 test_column from test_table where <column_test> = 'XXX'; ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com