IS Null Clause (OLAP)

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Doradus Query Language: IS Null Clause

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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 Quantifier Functions 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