Nested while is not working

Question

Nested while is not working

prabhakaran.ece

SSC Rookie

Points: 34
More actions
October 13, 2008 at 8:58 pm

#199362

PLease find my code here.
begin
declare @i int,@j int,@name varchar(20)
SET @i = 5
SET @j-2 = 3
SET @name ='Prabhakaran'
WHILE @i > 0
BEGIN
WHILE @j-2>0
BEGIN
Print @name
Print @j-2
SET @j-2 = @j-2 - 1
END
SET @i = @i -1
END
End

Viewing 8 posts - 1 through 7 (of 7 total)

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Jeff Moden SSC Guru Points: 1004365 More actions · Answer 1

You should tell us why you'll need nested While loops... typically, that's a recipe for a huge RBAR performance problem and it can usually be avoided. 😉

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

Jeff Moden SSC Guru Points: 1004365 More actions · Answer 2

You need to include the intial value of @j-2 in the @I loop or it just counts down in one iteration of @I and stays there.

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

Matt Miller (4) SSC Guru Points: 124210 More actions · Answer 3

Jeff Moden (10/13/2008)
Last, but not least, you need to include the intial value of @j-2 in the @I loop or it just counts down in one iteration of @I and stays there.

Agreed - that's more than likely where the confusion is.

----------------------------------------------------------------------------------
Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?

patriwala Old Hand Points: 303 More actions · Answer 4

hi,

your code is working perfect.

you set the variable value to it's condition then what to do.

SET @i = 5

SET @j-2 = 3

SET @name ='test'

WHILE @i > 0

BEGIN

print @i

WHILE @j-2>0

BEGIN

Print @name + '-' + cast(@j as varchar)

--here you set j value b'cz it's global variable

SET @j-2 = @j-2 - 1

END

--now here set and check code

SET @j-2 = 3

SET @i = @i -1

END

End

if i m getting right then?

thnx

Jeff Moden SSC Guru Points: 1004365 More actions · Answer 5

Still, the code is doomed to be comparatively slow because of the loops. If we knew the actual problem this was supposed to solve, perhaps we could find a proper set based solution for the problem. 😉

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)

noeld SSC Guru Points: 96590 More actions · Answer 6

By this time I think the PO is not longer with us (no pun intended)

* Noel

Jeff Moden SSC Guru Points: 1004365 More actions · Answer 7

noeld (10/14/2008)
By this time I think the PO is not longer with us (no pun intended)

Heh, agreed. It's a shame, too. I would have liked to take a crack at whatever they thought they needed a double loop for... maybe even if it was homework.:P

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)