Difference Between Cursor and While

Hi Kunal,

Cursor :

A cursor is a set of rows together with a pointer that identifies a current row.

In other word, Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis, its like record-set in the ASP and visual basic.

Example,

DECLARE @AccountID INT
DECLARE @getAccountID CURSOR
SET @getAccountID = CURSOR FOR
SELECT Account_ID
FROM Accounts
OPEN @getAccountID
FETCH NEXT
FROM @getAccountID INTO @AccountID
WHILE @@FETCH_STATUS = 0
BEGIN
PRINT @AccountID
FETCH NEXT
FROM @getAccountID INTO @AccountID
END
CLOSE @getAccountID
DEALLOCATE @getAccountID

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

While:

        Sets a condition for the repeated execution of an SQL statement or statement block. The statements are executed repeatedly as long as the specified condition is true. The execution of statements in the WHILE loop can be controlled from inside the loop with the BREAK and CONTINUE keywords.

Syntax:

WHILE Boolean_expression       { sql_statement | statement_block | BREAK | CONTINUE } 

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

Thanks & Regards
----------------
Chintan Rathod