WHILE statement [T-SQL]

Description

Provides repeated execution of a statement or compound statement.

Syntax

WHILE expression
... statement

Examples

Example 1

Illustrates the use of WHILE:

WHILE (SELECT AVG(unit_price) FROM Products) < 30 
BEGIN
	DELETE FROM Products
	WHERE UnitPrice = MAX(UnitPrice)
	IF ( SELECT MAX(UnitPrice) FROM Products ) < 50 
		BREAK
END

The BREAK statement breaks the WHILE loop if the most expensive product has a price less than $50. Otherwise the loop continues until the average price is greater than $30.

Usage

The WHILE conditional affects the performance of only a single SQL statement, unless statements are grouped into a compound statement between the keywords BEGIN and END.

The BREAK statement and CONTINUE statement can be used to control execution of the statements in the compound statement. The BREAK statement terminates the loop, and execution resumes after the END keyword, marking the end of the loop. The CONTINUE statement causes the WHILE loop to restart, skipping any statements after the CONTINUE.

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Standards

Permissions

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