A combined condition results from connecting conditions with one of the logical operators AND or OR. The general format is:

condition { {AND} condition } ... {OR}

In the general format, condition may be any of the following:

- a simple condition
- a negated simple condition
- a combined condition
- a negated combined condition; that is, a "NOT" followed by a combined condition enclosed in parentheses

Parentheses may be used in a complex condition to alter the rules of evaluation. Parentheses must be made in matched pairs and must be placed in such a way so that the enclosed symbols constitute a well-defined condition.

The truth value of a combined condition using AND is true only when both component conditions are true. The truth value of a combined condition using OR is true when either or both of the component conditions are true.