Thanks for a good question. I got it right, but I thought that perhaps only one such NULL INSERT would be allowed. After reading the BOL entry and trying it out, I see that you can INSERT many such rows.
Odd behavior, at least to me, as it seems the "correct" interpretation of this should be "only permit the INSERT if the constraint condition evaluates to TRUE."
Anyone here know if this is an ANSI-compliant implementation? Is this how constraints work in MySQL, Oracle, DB2? Just curious....
Learned something new and got my point!