Re: Quick SQL question . . .
Fran Fabrizio <ffabrizio@mmrd.com>
From: Fran Fabrizio <ffabrizio@mmrd.com>
To: "Peter E. Chen" <pchen3@jhmi.edu>, pgsql-general@postgresql.org
Date: 2002-05-09T19:54:33Z
Lists: pgsql-general
Perhaps a little on the hacky side but.... select count(1) from some_table group by identno order by 1 desc limit 1; If the result is anything other than 1, it's not unique. Sorry for the hacky nature, this is the "thought about it for 10 seconds" version. :-) -Fran 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? > >Peter > > > > >---------------------------(end of broadcast)--------------------------- >TIP 4: Don't 'kill -9' the postmaster > >