IS NULL Clause

A scalar or link field can be tested for nullity by using the clause field IS NULL. Examples:

LastName IS NULL

InternalRecipients IS NULL

Sender.MessageAddress.Person.Manager IS NULL

The last example above uses a link path (described later). See the section Quantifiers with IS NULL for examples of how IS NULL interacts with implicitly and explicitly quantified link paths.

An IS NULL clause can be negated with NOT as a clause prefix:

NOT LastName IS NULL

NOT InternalRecipients IS NULL

NOT Sender.MessageAddress.Person.Manager IS NULL