my sql and group by problem?!

[Jason Engel]

TABLE2 --------------
id : link : title
1) 1 : alpha : title1
2) 2 : alpha : title2
3) 3 : alpha : title3
4) 4 : alpha : title4
-----------------------

select max(id), title from table2 group by link

returns:

max(id) : title
1) 4 : title1

WHY DOES IT NOT RETURN (pulls hair out!)

max(id) : title
1) 4 : title4

[Bill Karwin]

Jason Engel wrote:

WHY DOES IT NOT RETURN (pulls hair out!)

max(id) : title
1) 4 : title4

You're applying the DWIM ("Do What I Mean") principle.

The MAX() aggregate function does not return the row on which the max
value occurs. It only returns one value -- the maximum value found in
*one* column, within the group. When you list other columns in the
select-list, the row from which to take the value is ambiguous. In some
RDBMS products, it's actually an error to list a column in the
select-list that you haven't also listed in the GROUP BY clause. MySQL
is a bit more permissive, but it does to resolve the ambiguity in what
is called a "vendor-dependent" way.

Regards,
Bill K.