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SQL LIKE and Rushmore optimization
Message
De
20/01/2006 07:34:56
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 8 SP1
OS:
Windows XP SP2
Network:
Windows XP
Database:
Visual FoxPro
Divers
Thread ID:
01088808
Message ID:
01088834
Vues:
13
Hi Sergey!
Thanks for response.
Unfortunately AT() and $ is not optimizable...
I try to create complex index expression like
INDEX ON "1"+UPPER(Description) TAG Test
and
SELECT * FROM table WHERE "1"+UPPER(Description) Like "1%HP%PRINTER"
to avoid not optimized lead "%"... all indexes in expression using for rushmore.. but report again "partial"..

I thinking about PHD tool... for optimize query... the database is too big.. and speed of query is not acceptable now....

Thanks
Denis.


>In VFP8 and earlier the expression in the LIKE that doesn't start with wildcard character but ends with '%' are only partialy optimaziable. I'm not sure if it'll be optimizable but you can try
>SET ANSI OFF
>...
>(UPPER(Description) = "HP" AND "PRINTER" $ UPPER(Description)) ;
>OR (UPPER(Description2) = "HP" AND "PRINTER" $ UPPER(Description2)) ;
>...
>
>
>>I need help to rushmore optimize query using LIKE... or maybe change sql expression code
>>Example of query
>>UPPER(Description) like "%HP%PRINTER" or UPPER(Description2) like "%HP%PRINTER" or UPPER(Manufacture) like "%HP%PRINTER" or UPPER(productgroup) like %HP%PRINTER"
>>
>>Finally.. I'v got SYS(3054) - partial.. only Deleted tag using for rushmore optimization...
>>
>>Any ideas how to optimize this query, or maybe another way to get same result
>>
>>Thanks
>>Denis.
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