You can use group parentheses to group a set of expressions. A group is a set of expressions that are explicitly combined with parentheses. You can only group a set of expressions that form a subclause (a set of expressions that can be logically treated as a single expression).
Use group parentheses to make complex expressions easier to understand or to force a certain order of evaluation. For example, when more than one OR expression occurs within a complex query, use parentheses to indicate which expression should be evaluated first.
By making a set of expressions a group, you ensure that the expressions of the group are treated together and evaluated first. Groups have a higher operator precedence than the logical operators AND, OR, and NOT. For more information about how queries are evaluated and operator precedence, see About Logical Operators and Operator Precedence.
Using Queries to Locate Resources Overview