is a symbol that specifies an action that is performed on one or more expressions. The following table shows valid operators. An expression can also contain the CASE or COALESCE expressions. For more information, see CASE Expression or COALESCE Expression.

Valid Operators
Operator	Description
+	adds
–	subtracts
*	multiplies
/	divides
=	equals
<>	does not equal
>	is greater than
<	is less than
>=	is greater than or equal to
<=	is less than or equal to
**	raises to a power
unary –	indicates a negative number
\|\|	concatenates

predicate

is an expression that returns true, false, or unknown.

Valid predicates are as follows.

Details

Overview of <sql-expression>

Simple expressions can be a single constant, variable, column name, or function. Complex expressions are two or more simple expressions that are joined by an operator or predicate.

Functions in Expressions

An expression can contain a SAS function or an aggregate function. SAS functions perform a computation or system manipulation on one or more arguments and return a value. Aggregate functions produce a statistical summary of data in the entire table that is listed in the FROM clause or for each group that is specified in a GROUP BY clause. If GROUP BY is omitted, then all the rows in the table are considered to be a single group. Aggregate functions reduce all the values in each row or column in a table to one summarizing or aggregate value. For example, the sum (one value) of a column results from the addition of all the values in the column.

Subqueries in Expressions

FedSQL allows a scalar subquery (contained in parentheses) at any point in an expression where a simple column value or constant can be used. In this case, a subquery must return a single value (that is, one row with only one column).

Order of Evaluation

The operators and predicates that are shown in the following table are listed in the order in which they are evaluated.

Expressions, Operators, and Predicates and Order of Evaluation
Group	Expressions, Operators, and Predicates	Description
0	( )	forces the expression enclosed to be evaluated first
1	CASE expression	See CASE Expression
2	**	raises to a power
	unary +, unary −	indicates a positive or negative number
3	*	multiplies
	/	divides
4	+	adds
	−	subtracts
5	\|\|	concatenates
6	[NOT] BETWEEN predicate	See BETWEEN Predicate
	DISTINCT predicate	See DISTINCT Predicate
	[NOT] EXISTS predicate	See EXISTS Predicate
	[NOT] IN predicate	See IN Predicate
	IS [NOT] TRUE predicate	See IS TRUE Predicate
	IS [NOT] FALSE predicate	See IS FALSE Predicate
	IS [NOT] MISSING predicate	See IS MISSING Predicate
	IS [NOT] NULL predicate	See IS NULL Predicate
	IS [NOT] UNKNOWN predicate	See IS UNKNOWN Predicate
	LIKE predicate	See LIKE Predicate
7	=	equals
	^=, <>	does not equal
	>	is greater than
	<	is less than
	>=	is greater than or equal to
	<=	is less than or equal to
8	AND	indicates logical AND
9	OR	indicates logical OR
10	NOT	indicates logical NOT

SAS missing values and null values always appear as the smallest value in the collating sequence.

You can use parentheses to group values or to nest mathematical expressions. Parentheses make expressions easier to read and can also be used to change the order of evaluation of the operators. Evaluating expressions with parentheses begins at the deepest level of parentheses and moves outward. For example, SAS evaluates A+B*C as A+(B*C), although you can add parentheses to make it evaluate as (A+B)*C for a different result.

<sql-expression>

Syntax

Arguments

constant

variable

alias

column

function

scalar-subquery

operator