Re: Quick SQL question . . .

On Thu, 9 May 2002, Peter E. Chen wrote:

 > 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?

SELECT identno, count(*) FROM some_table
  GROUP BY 1 HAVING COUNT(*) = 1;

Regards Herbie
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Herbert Liechti                                  http://www.thinx.ch
ThinX networked business services    Adlergasse 5, CH-4500 Solothurn
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