Re: Quick SQL question . . .

Is it just me or do the suggestion made look wrong to anyone else?

Anyway, this is the closest to my mind and I think what I think is the mistake
is just a typo. So I would use.

SELECT identno, count(identno)
   FROM some_table
   GROUP BY identno
   HAVING count(identno) > 1

or even

SELECT count(1) FROM (
   SELECT count(identno)
      FROM some_table
      GROUP BY identno
      HAVING count(identno) > 1) a

either one of which will return one of more rows if Peter's uniqueness test
fails.

Right, now someone can correct me :)


On Thu, 9 May 2002, Marie G. Tuite wrote:
> Try
>
> select identno, count(identno) from some_table group by identno having
> count(identno) >=1;
>
>
> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Peter E. Chen
> Sent: Thursday, May 09, 2002 2:39 PM
> To: pgsql-general@postgresql.org
> Subject: [GENERAL] Quick SQL question . . .
>
>
> Can anyone tell me what is the easiest way for me to tell if a column is
> unique or not?  I tried using DISTINCT ON and COUNT together in a SELECT
> statement, but I can't seem to get the query to work:
>
> SELECT DISTINCT ON (identno) count(identno) FROM some_table;
>
> I was trying to figure out if the # of unique entries for a particular
> column is equal to the # of total entries for that column.
>
> Any suggestions?
>
> Peter
>

--
Nigel J. Andrews
Director

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