* bened...@apache.org <bened...@apache.org> [22/06/13 17:37]: > I believe that is a MySQL specific concept. This is one problem with > mimicking SQL – it’s not one thing! > > In T-SQL, a Boolean expression is TRUE, FALSE or UNKNOWN[1], and a NULL value > submitted to a Boolean operator yields UNKNOWN. > > IF (X) THEN Y does not run Y if X is UNKNOWN; > IF (X) THEN Y ELSE Z does run Z if X is UNKNOWN. > > So, I think we have evidence that it is fine to interpret NULL > as “false” for the evaluation of IF conditions.
NOT FOUND handler is in ISO/IEC 9075-4:2003 13.2 <handler declaration> In Cassandra results, there is no way to distinguish null values from absence of a row. Branching, thus, without being able to branch based on the absence of a row, whatever specific syntax is used for such branching, is incomplete. More broadly, SQL/PSM has exception and condition statements, not just IF statements. -- Konstantin Osipov, Moscow, Russia
