Re: A select DISTINCT query? - followup Q

In article <1201455192(dot)28880(dot)105(dot)camel(at)prix(dot)pricom(dot)com(dot)au>,
Phil Rhoades <phil(at)pricom(dot)com(dot)au> writes:

> People,
>> select count(*) as cnt, name from tst group by name having count(*) = 1

> This worked for my basic example but not for my actual problem - I get
> "column comment must appear in the GROUP BY clause or be used in an
> aggregate function" errors so I have a related question:

> With table:

> name comment

> 1 first comment
> 2 second comment
> 3 third comment
> 3 fourth comment
> 4 fifth comment
> 5 sixth comment

> - how can I use something like the previous select statement but where
> the comment field does not appear in the "group by" clause and gives the
> following result:

> 1 first comment
> 2 second comment
> 4 fifth comment
> 5 sixth comment

If you want to select both columns, but have uniqueness over the first
only, you can use a derived table:

SELECT tbl.name, tbl.comment
FROM tbl
JOIN (SELECT name FROM tbl GROUP BY name HAVING count(*) = 1) AS t
ON t.name = tbl.name