Friday, June 17, 2011

SQL SERVER – Simple Example of WHILE Loop With CONTINUE and BREAK Keywords

This is question is one of those question which is very simple and most of the users get it correct, however few users find it confusing for first time. I have tried to explain the usage of simple WHILE loop in first example. BREAK keyword will exit the stop the while loop and control is moved to next statement after the while loop. CONTINUE keyword skips all the statement after its execution and control is sent to first statement of while loop. Run following examples in Query Editor and see the result. This is very easy to understand example.


1) Example of WHILE Loop
DECLARE @intFlag INT
SET
@intFlag = 1
WHILE (@intFlag <=5)
BEGIN
PRINT
@intFlag
SET @intFlag = @intFlag + 1
END
GO

ResultSet:
1
2
3
4
5
2) Example of WHILE Loop with BREAK keyword
DECLARE @intFlag INT
SET
@intFlag = 1
WHILE (@intFlag <=5)
BEGIN
PRINT
@intFlag
SET @intFlag = @intFlag + 1
IF @intFlag = 4
BREAK;
END
GO

ResultSet:
1
2
3
3) Example of WHILE Loop with CONTINUE and BREAK keywords
DECLARE @intFlag INT
SET
@intFlag = 1
WHILE (@intFlag <=5)
BEGIN
PRINT
@intFlag
SET @intFlag = @intFlag + 1
CONTINUE;
IF @intFlag = 4 -- This will never executed
BREAK;
END
GO

ResultSet:
1
2
3
4
5
Reference : Pinal Dave (http://blog.SQLAuthority.com)


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