AND (Transact-SQL)

Artykuł
12/08/2014

Combines two Boolean expressions and returns TRUE when both expressions are TRUE. When more than one logical operator is used in a statement, the AND operators are evaluated first. You can change the order of evaluation by using parentheses.

Ikona łącza do tematu Transact-SQL Syntax Conventions

Składnia

boolean_expression AND boolean_expression

Arguments

boolean_expression
Is any valid expression that returns a Boolean value: TRUE, FALSE, or UNKNOWN.

Result Types

Boolean

Result Value

Returns TRUE when both expressions are TRUE.

Uwagi

The following chart shows the outcomes when you compare TRUE and FALSE values by using the AND operator.

	TRUE	FALSE	UNKNOWN
TRUE	TRUE	FALSE	UNKNOWN
FALSE	FALSE	FALSE	FALSE
UNKNOWN	UNKNOWN	FALSE	UNKNOWN

Examples

A. Using the AND operator

The following example selects information about employees who have both the title of Marketing Assistant and more than 41 vacation hours available.

USE AdventureWorks2012;
GO
SELECT  BusinessEntityID, LoginID, JobTitle, VacationHours 
FROM HumanResources.Employee
WHERE JobTitle = 'Marketing Assistant'
AND VacationHours > 41 ;

B. Using the AND operator in an IF statement

The following examples show how to use AND in an IF statement. In the first statement, both 1 = 1 and 2 = 2 are true; therefore, the result is true. In the second example, the argument 2 = 17 is false; therefore, the result is false.

IF 1 = 1 AND 2 = 2
BEGIN
   PRINT 'First Example is TRUE'
END
ELSE PRINT 'First Example is FALSE';
GO

IF 1 = 1 AND 2 = 17
BEGIN
   PRINT 'Second Example is TRUE'
END
ELSE PRINT 'Second Example is FALSE' ;
GO