Performs an arithmetic operation that adds two numbers.
A valid Multidimensional Expressions (MDX) expression that returns a numeric value.
A value with the data type of the parameter that has the higher precedence.
Both expressions must be of the same data type, or one expression must be able to be implicitly converted to the data type of the other expression. If one expression evaluates to a null value, the operator returns the result of the other expression.