Execute the following Microsoft SQL Server T-SQL training example script in Management Studio Query Editor to demonstrate the design of a WHILE loop.

-- T-SQL WHILE loop

SET nocount  ON

USE Northwind;

-- T-SQL local variables

DECLARE  @Customer NCHAR(5),

         @Limit    INT,

         @RowNum   INT

SET @Limit = 7

-- T-SQL TOP function  

SELECT TOP 1 @Customer = CustomerID

FROM   Northwind.dbo.Customers

SET @RowNum = 0

WHILE @RowNum < @Limit

  BEGIN

    ------------------------------------------------------------------

    -- ADD PROCESSING HERE

    ------------------------------------------------------------------

    SET @RowNum = @RowNum + 1

    PRINT Convert(VARCHAR,@RowNum) + ' ' + @Customer -- in messages

    SELECT TOP 1 @Customer = CustomerID

    FROM   Northwind.dbo.Customers

    WHERE  CustomerId > @Customer

  END -- while

GO

/* Messages

1 ALFKI

2 ANATR

3 ANTON

4 AROUT

5 BERGS

6 BLAUS

7 BLONP

*/

------------

Related link:

http://www.sqlusa.com/bestpractices/whilelooptablevariable/