[dba-SQLServer] NULLs

 The first is the implication that any null column cannot be
> indexed, or even if the system allows it, the index will never be used.

=======What you're suggesting is that even though SQL Server allows the 
index to be set, it won't use it -- I'd be surprised if that's the case and 
not surprised at all -- paradox... but we're dealing with MS.

>
> At any rate, if the conjecture is true, then by extension one should 
> arrange
> the columns in order of frequency of use.(in indexes and queries). I think
> that for a small database, a few hundred megs let's say, the performance
> difference will be minimal even if the conjecture is true. But medium to
> large databases (20 gigs to a terabytem say) the difference, if any, might
> be significant.

========Well, let me say this -- I will be surprised if this matters. You'd 
think, if this were really the case in SQL Server, that it'd be well known 
already.

Susan H.