A relational condition specifies a comparison, substring comparison test, bit logic test, date comparison, numeric test or alphanumeric test to be performed. Relational conditions can be logically combined, with AND or OR, to form a logical expression. If they are combined, the following rules apply:

• AND statements are evaluated before OR statements unless parentheses are used to change the order of evaluation; expressions inside parentheses are always evaluated first. (Nesting of parentheses is limited only by the amount of storage available.)
• The symbols & (AND) and | (OR) can be used instead of the words.