Chapter 1: DataWindow Operators and Expressions

Arithmetic operators in DataWindow expressions

When you write an expression, you can use the following arithmetic operators:

**Table 1-5: Using expressions with arithmetic operators**
Operator	Meaning	Example
+	Addition	SubTotal + Tax
-	Subtraction	Price - Discount
*	Multiplication	Quantity * Price
/	Division	Discount / Price
^	Exponentiation	Rating ^ 2.5

Multiplication and division

Multiplication and division are carried out to full precision (16–18 digits). Values are rounded:

**Table 1-6: Value rounding in DataWindow expressions**
Expression	Value
20.0/3	6.666666666666667
3*(20.0/3)	20
Truncate(20.0/3,4)	6.6666

Calculations with NULL

When you form an arithmetic expression that contains a NULL value, the expression becomes NULL. Thinking of NULL as undefined makes this easier to understand. For example, when a NULL column is multiplied by 5, the entire expression also evaluates to NULL. Use the IsNull function to explicitly check for the NULL value.

Boolean expressions that contain a NULL value evaluate to FALSE rather than to NULL. For more information, see “Relational operators in DataWindow expressions”.

Relational operators in DataWindow expressions

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