Just want to add:
> 1) Display the rows with the highest date per id. That gives as many rows as
> ids exist.
>
> select id, max(date) from mytable group by id;
>
> gives just the id and the date, not the other values. I think of doing this
> in two steps:
select id, max(date),min,value,max from mytable group by id,min,value,max;
Gives too many rows. I don't know why. If I can manage to fix the query above
just to output one row per id I can solve it.
Marco