
expression
 is generally a sequence of operands and operators that form
a set of instructions that are performed to produce a resulting value. You
use expressions in SAS program statements to create variables, assign values,
calculate new values, transform variables, and perform conditional processing.
SAS expressions can resolve to numeric values, character values, or Boolean
values.

operands
 are constants or variables that can be numeric or
character.

operators
 are symbols that represent a comparison, arithmetic calculation,
or logical operation; a SAS function; or grouping parentheses.
 simple expression
 is an expression with no more than one operator. A simple
expression can consist of a
single
 constant
 variable
 function.

compound expression
 is an expression that includes several operators. When SAS
encounters a compound expression, it follows rules to determine the order
in which to evaluate each part of the expression.
The following are examples of SAS expressions:
3
x
x+1
age<100
trim(last)', 'first
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.