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.

are symbols that represent
a comparison, arithmetic calculation, or logical operation; a SAS
function; or grouping parentheses.

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.

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 about WHERE
expressions, see WHERE-Expression Processing.