Introduction to SQL Server OR operator

Introduction to SQL Server OR operator

The SQL Server OR is a logical operator that allows you to combine two Boolean expressions. It returns TRUE when either of the conditions evaluates to TRUE.

The following shows the syntax of the OR operator:

1	boolean_expression OR boolean_expression

In this syntax, the boolean_expression is any valid Boolean expression that evaluates to true, false, and unknown.

The following table shows the result of the OR operator when you combine TRUE, FALSE, and UNKNOWN:

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

When you use more than one logical operator in a statement, SQL Server evaluates the OR operators after the AND operator. However, you can use the parentheses to change the order of evaluation.

SQL Server OR operator examples

See the following production.roducts table from the sample database.

A) Using OR operator example

The following example finds the products whose list price is less than 200 or greater than 6,000:

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SELECT     product_name,     list_price FROM     production.products WHERE     list_price < 200 OR list_price > 6000 ORDER BY     list_price;

B) Using multiple OR operators example

The following statement finds the products whose brand id is 1, 2, or 4:

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SELECT     product_name,     brand_id FROM     production.products WHERE     brand_id = 1 OR brand_id = 2 OR brand_id = 4 ORDER BY     brand_id DESC;

You can replace multiple OR operators by the IN operator as shown in the following query:

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SELECT     product_name,     brand_id FROM     production.products WHERE     brand_id IN (1, 2, 3) ORDER BY     brand_id DESC;

C) Using OR operator with AND operator example

Consider the following example:

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SELECT     product_name,     brand_id,     list_price FROM     production.products WHERE     brand_id = 1       OR brand_id = 2       AND list_price > 500 ORDER BY     brand_id DESC,     list_price;

In this example, we used both OR and AND operators. As always, SQL Server evaluated the AND operator first. Therefore, the query returned the products whose brand id is 2 and the list price is greater than 500 or the products whose brand id is 1.

To find the products whose brand id is 1 or 2 and list price is greater than 500, you use the parentheses as shown in the following query:

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SELECT     product_name,     brand_id,     list_price FROM     production.products WHERE     (brand_id = 1 OR brand_id = 2)      AND list_price > 500 ORDER BY     brand_id;

In this tutorial, you have learned how to use the SQL Server OR operator to form a condition by combining two Boolean expressions.