SAS 9.1.3 Language Reference: Concepts, Third Edition, Volumes 1 and 2

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.

WHERE expressions

is a type of SAS expression that is used within a WHERE statement or WHERE= data set option to specify a condition for selecting observations for processing in a DATA or PROC step. For syntax and further information on WHERE expressions, see Chapter 12, "WHERE-Expression Processing," on page 197 and SAS Language Reference: Dictionary