>If you known that on the group the expression is constant, then
>min=max=any and these are equals:
>

>SELECT item,MIN(exp)  FROM test GROUP BY item
>SELECT item,MAX(exp)  FROM test GROUP BY item
>SELECT item,exp       FROM test GROUP BY item,exp
>SELECT item,exp       FROM test GROUP BY exp,item
>
>set engine 70
>SELECT item,exp FROM test GROUP BY item
>

>
>This is a very special case,
>and a lot of times it conceals a bad planning of the database;
>then it is difficult to justify the implementation of ANY()
>

Actually, I think this situation comes up most when you want to select several fields from a parent along with some information from a child. For example:

SELECT Customer.CustomerID, CompanyName, MAX(OrderDate) ;
  FROM Customer ;
    JOIN Order ;
      ON Customer.CustomerID = Order.CustomerID ;
  GROUP BY CustomerID

In this case, of course, either solution--adding the field to the GROUP BY or wrapping it with MAX()--works.

Tamar