Unknown Operators

Atfinity's rule language has a third truth value, unknown, for information that has not been provided yet (see Unknown & Three-Valued Logic). These operators let you handle unknown values explicitly:

• unknown and known test whether a value is missing or present.
• SNEAKY ignores an expression when the information it needs is not available.
• The *_OF_ANY operators (such as SUM_OF_ANY and AVG_OF_ANY) aggregate only the values that are available, ignoring any that are unknown.