Loops in SQL Server

In SQL Server, a loop is the technique where a set of SQL statements are executed repeatedly until a condition is met.

SQL Server supports the WHILE loop. The execution of the statements can be controlled from within the WHLE block using BREAK and CONTINUE keywords.

Syntax:

WHILE <condition>
    SQL Statement | statement_block | BREAK | CONTINUE

Boolean_expression : A boolean expression that returns TRUE or FALSE.

sql_statement | statement_block : A single or a group of SQL statements (statement block). Statement block should be enclosed with BEGIN and END keywords.

BREAK: Causes the flow to exit from the innermost WHILE loop. Statements after the END keyword are executed after the BREAK.

CONTINUE: Causes the WHILE loop to restart. It ignores all statements after the CONTINUE keyword.

While Loop

The following example uses the WHILE loop to print numbers.

Example: WHILE Loop

DECLARE @i INT = 10;
 
WHILE @i &lt;= 30
	BEGIN
		PRINT (@i);
		SET @i = @i + 10;
	END;

The following displays the result in SSMS.