From: | Mauro Delfino <maurodelfino(at)gmail(dot)com> |
---|---|
To: | Bruno Wolff III <bruno(at)wolff(dot)to>, Mauro Delfino <maurodelfino(at)gmail(dot)com>, pgsql-bugs(at)postgresql(dot)org |
Subject: | Re: BUG #1698: Different behavior in UNIQUE and DISTINCT |
Date: | 2005-06-13 13:12:38 |
Message-ID: | 8d465be205061306124d947056@mail.gmail.com |
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Lists: | pgsql-bugs |
Yes I'm sure. I was created right before filling it.
Thanks,
Mauro
2005/6/3, Bruno Wolff III <bruno(at)wolff(dot)to>:
>
> On Thu, Jun 02, 2005 at 20:22:07 +0100,
> Mauro Delfino <maurodelfino(at)gmail(dot)com> wrote:
> >
> > I have the these two tables:
> > CREATE TABLE table_one
> > ( field1 VARCHAR(255) );
> >
> > CREATE TABLE table_two
> > ( field1 VARCHAR(255) UNIQUE );
> >
> > table_one has 500k records. I certify that all strings are distinct with
> > this query:
> > SELECT DISTINCT field1 FROM table_one;
> > The query results 500k rows.
> >
> > But if I try to insert the records of table_one into table_two with the
> > following command:
> > INSERT INTO table_two (field1) (SELECT field1 FROM table_one);
> > This error occurs:
> > ERROR: duplicate key violates unique constraint "table_two_field1_key"
> >
> > What happened? DISTINC and UNIQUE have different algorithms to determine
> > when two strings are equal?
>
> Are you sure table_two is empty when you do this?
>
--
Mauro Delfino
maurodelfino(at)gmail(dot)com
(48) 9933-6933
(MCDBA/MCSE/MCP+I/IBM Lotus CLS)
Microsoft SQL Server Official Beta Tester
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