InterSystems SQL Reference
A unary operator that
returns an expression as a negative, numeric value.
Unary operators perform an operation on only one expression of any of
the data types of the numeric data type category.
(Negative) is an InterSystems SQL extension.
The following example returns three numeric fields: the Age column from
Sample.Person; the (Negative) value of the average of Age; and the
Age minus the average age:
-(AVG(age)) AS NegAvg,
Age-AVG(Age) AS AgeRelAvg