> Now here is an interesting question... If the first field in a
> multi-segmented index is NULL, or has an indeterminant value, how can
> you sort the rest of the fields? If you do, you are basically saying
> that the NULLs are all equal to each other.
So a query that produces a list of all bugs with unknown fix in bug number
order would be saying that they all have the same fix? Nope. It's just a
list of unknowns in some secondary order. What the unknowns are isn't the
same but that they are unknown is.
James Day, MySQL Senior Support Engineer, Sun Microsystems