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От Schlobohm, Jack
Тема RE:
Дата
Msg-id 15E3AECB85501-01@WorldSecure_Server__smtp-gw.us.dnb.com_
обсуждение исходный текст
Ответ на  (Lengyel Ferenc <lengyel@hell.ditec.sk>)
Список pgsql-sql
Can I be removed from this mailing list?

> -----Original Message-----
> From:    Yury Don [SMTP:yura@vpcit.ru]
> Sent:    Monday, October 30, 2000 6:55 AM
> To:    pgsql-sql@postgresql.org
> Subject:    Re: [SQL]
> 
> Hello Lengyel,
> 
> Once, Monday, October 30, 2000, 5:36:23 PM, you wrote:
> 
> LF> Hello everybody!
> LF> I need some help with a simple query.
> LF> I've got a problem with getting a maximum value from a very large
> table
> LF> (10000000+ rows):
> LF> I have table:
> LF> CREATE TABLE TABLE_A
> LF> (
> LF> COL1 INT,
> LF> COL2 INT,
> LF> CONSTRAINT PK PRIMARY KEY (COL1, COL2)
> LF> )
> 
> LF> and when I want to get the maximum value for col1:
> LF> SELECT MAX(COL1) FROM TABLE_A WHERE COL2 = 1
> LF> it takes a large amount of time.
> LF> I created an index on column COL1, but it doesn't work.
> 
> You need to create index on COL2.
> 
> -- 
> Best regards,
>  Yury  ICQ 11831432
>  mailto:yura@vpcit.ru
> 
> 



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