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RE: Re(2): optimize sql

From: Henry Lafleur <HLafleur(at)phoenixforge(dot)com>
To: pgsql-sql(at)fc(dot)emc(dot)com(dot)ph, pgsql-sql(at)postgresql(dot)org, reedstrm(at)rice(dot)edu
Subject: RE: Re(2): optimize sql
Date: 2000-07-27 13:15:17
Message-ID: E332B20358CDD1118D7A00A0C995F75A9145A3@XSERVER (view raw or flat)
Thread:
Lists: pgsql-sql
If you know that 't' will always be the highest character in the active
field for all records:

SELECT name FROM office, office_application
WHERE code = office_code
GROUP BY name
HAVING MAX(active) < 't'

Of course, if you have an active that is 'z' for example, then this won't
work. I think this should work also regardless of max(active) for the table:

SELECT name FROM office, office_application
WHERE code = office_code AND active <= 't'
GROUP BY name
HAVING MAX(active) < 't'
UNION
SELECT name FROM office, office_application
WHERE code = office_code AND active >= 't'
GROUP BY name
HAVING MIN(active) > 't'

Henry


-----Original Message-----
From: pgsql-sql(at)fc(dot)emc(dot)com(dot)ph [mailto:pgsql-sql(at)fc(dot)emc(dot)com(dot)ph]
Sent: Wednesday, July 26, 2000 9:40 PM
To: pgsql-sql(at)postgresql(dot)org; reedstrm(at)rice(dot)edu
Subject: Re(2): [SQL] optimize sql


reedstrm(at)rice(dot)edu writes:
>How does the output of the above differ from:
>
>SELECT name FROM office, office_application 
>WHERE code = office_code 
>AND active != 't';
>
>Without knowing the table structures (which tables to active, code, 
>and office_code belong to?) it's hard to suggest much else.
>
>Ross


The name and code fields belong to office table. While
office_code and active fields belong to office_application table.
The name field have duplicates and among the duplicates,
only one active field is TRUE. I just wanted to get name field
that has no TRUE active field. Any other idea? Thanks.

sherwin

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Subject: Compile
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Subject: Antw: Re: Large text insertion

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