Hm, I am a little confused because of the missing comma before the CONSTRAINT declaration. That does not seem to be required based on a first test. But I checked my BOL to see verify the syntax, and this is what I found (excerpt):

( { <column_definition> | <computed_column_definition>

| <column_set_definition> }

[ <table_constraint> ] [ ,...n ] )

I cannot derive any meaning from that. Can anyone interpret this notation?

Anyways, it looks like the web contains an updated version of the syntax which makes more sense:

( { <column_definition> | <computed_column_definition>

| <column_set_definition> | [ <table_constraint> ] [ ,...n ] } )

http://msdn.microsoft.com/en-us/library/ms174979(v=sql.105).aspx

However this doesnt explain why it is possible to add the table constraint without a comma between the last column specification and the constraint itself.

Any ideas?