Hugo Kornelis (4/30/2013)
For WHERE and IF, a logic result of True qualifies, and False and Unknown do not qualify.For CHECK constraints, a logic result of True or Unknown qualifies and False doesn't.
Thanks for pointing this out, Hugo. I wonder why MS would inflict this on the unwary:
A CHECK constraint returns TRUE when the condition it is checking is not FALSE for any row in the table.
As Hugo pointed out, SQL Server uses 3-part Boolean logic, where it can't be proven categorically that (NOT FALSE) = TRUE.
Jason Wolfkill