When synthesizing an ON constraint from a USING or NATURAL, if the left-hand side is coming from a RIGHT JOIN, be sure to set the EP_CanBeNull flag so that the optimizer knows to check for NULL even if the column has a NOT NULL constraint. Fix for the problem reported by [forum:/forumpost/4fc70203b61c7e12|forum post 4fc70203b61] (tags: trunk)

When synthesizing an ON constraint from a USING or NATURAL, if the left-hand side is coming from a RIGHT JOIN, be sure to set the EP_CanBeNull flag so that the optimizer knows to check for NULL even if the column has a NOT NULL constraint. Fix for the problem reported by [forum:/forumpost/4fc70203b61c7e12|forum post 4fc70203b61] (tags: trunk)