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I need help with using a temp table in a Stored Procedure in SQL SERVER 2008 R2

Hi Experts,
I have created a Stored Procedure in SQL Server 2008 R2. I created a few @-variables and named them @Principal, @Interest, @TotalPrincipal,@TotalInterest. In my stored procedure I loop through a Temp Table I created. As I loop through the table I add @Principal to @TotalPrincipal, and I add @Interest to @TotalInterest. Once I am done with the loop I want my Stored Procedure to return the @TotalPrincipal and @TotalInterest values. How can I do this? Do I need another temp table? I have included a sample of my code. Thanks in advance for your help. -mrotor :-)

Here's a sample of my code:

Create table #DataTemp
(
      PK int Identity(1,1)
      Principal varchar(50),
      Interest varchar(50),
)
INSERT INTO #DataTemp(Principal,Interest)
SELECT Principal, Interest FROM RecordTrans

DECLARE @COUNTRAWDATA int;
SELECT @COUNTRAWDATA = COUNT(*) FROM #DataTemp

DECLARE @intCounter int;
SET @intCounter = 1

DECLARE @PRINCIPAL float;
DECLARE @TOTALPRINCIPAL float;
DECLARE @INTEREST float;
DECLARE @TOTALINTEREST float;

WHILE @intCounter <= @COUNTRAWDATA
BEGIN

SELECT @PRINCIPAL = Principal,
@INTEREST = Interest
FROM #DataTemp WHERE PK = @intCounter

      @TOTALPRINCIPAL = @TOTALPRINCIPAL + @PRINCIPAL
@TOTALINTEREST = @TOTALINTEREST + @INTEREST

      --INCREMENT MY COUNTER
      SELECT @intCounter = @intCounter + 1
END

dsacker

At the end of your stored proc, simply:

SELECT  Principal,
        Interest
FROM    #DataTemp

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SOLUTION

Jim Horn

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dsacker

My bad. Misread the request.

BAKADY

Do you really need help!!!

What are the data types of Principal and Interest from RecordTrans???
Are they numeric/float or char/varchar???
Have you consider I/O and other Performances???

All that you need is :

SELECT @TOTALPRINCIPAL = SUM(Principal), @TOTALINTEREST = SUM(Interest) FROM RecordTrans GROUP BY 0;
GO

SELECT @TOTALPRINCIPAL as TotalPrincipal, @TOTALINTEREST as TotalInterest;
GO

Regards

NOTE: are Principal and Interest Text? if yes you need to convert them to numeric.

WRONG:

Create table #DataTemp
(
PK int Identity(1,1)
Principal varchar(50), <<<< WRONG DATA TYPE FOR NUMERIC OPERATIONS
Interest varchar(50), <<<< WRONG DATA TYPE FOR NUMERIC OPERATIONS
)
INSERT INTO #DataTemp(Principal,Interest)
SELECT Principal, Interest FROM RecordTrans <<<< WRONG: USE SUM(..) FUNCTION

DECLARE @COUNTRAWDATA int; <<< YOU DON'T REALLY NEED THIS, SAVE MEMORY FOR IMPORTANT THINGS
SELECT @COUNTRAWDATA = COUNT(*) FROM #DataTemp

DECLARE @intCounter int;
SET @intCounter = 1

DECLARE @PRINCIPAL float;
DECLARE @TOTALPRINCIPAL float;
DECLARE @INTEREST float;
DECLARE @TOTALINTEREST float;

WHILE @intCounter <= @COUNTRAWDATA <<< YOU DON'T NEED THIS, SAVE PROCESSOR FOR IMPORTANT THINGS
FOR
BEGIN

SELECT @PRINCIPAL = Principal,
@INTEREST = Interest
FROM #DataTemp WHERE PK = @intCounter <<< YOU DON'T NEED THIS EITHER , SAVE I/O HDD AND MEMORY FOR IMPORTANT THINGS

@TOTALPRINCIPAL = @TOTALPRINCIPAL + @PRINCIPAL
@TOTALINTEREST = @TOTALINTEREST + @INTEREST

--INCREMENT MY COUNTER
SELECT @intCounter = @intCounter + 1
END

Scott Pletcher

Your original code is missing the "SET" keyword: SQL Server's T-SQL requires "SET" when setting a variable:
...
SET @TOTALPRINCIPAL = @TOTALPRINCIPAL + @PRINCIPAL
SET @TOTALINTEREST = @TOTALINTEREST + @INTEREST
...

But, even better, SQL allows you to do aggregating/summary functions -- such as SUM(), COUNT(), AVG() -- on an entire table or specified groupings of rows in the table.

For example, you can get the totals you want in this case using code like this:

DECLARE @COUNTRAWDATA int;
DECLARE @PRINCIPAL float;
DECLARE @TOTALPRINCIPAL float;
DECLARE @INTEREST float;
DECLARE @TOTALINTEREST float;

SELECT
@COUNTRAWDATA = COUNT(*),
@PRINCIPAL = SUM(Principal),
@INTEREST = SUM(Interest)
FROM #DataTemp

Zberteoc

This is a typical procedural programming approach in the database context. You have to understand that in SQL language you don't need to loop through every record in a table like in a recordset in an application. In SQL language you should avoid the loops except when there is no other way, which is really rare.

Your code is an example of resource wasting and poor performance. In order to sum columns all you need is to use aggregate functions and grouping feature, if you group by some subsets. All in all you don't even need a stored procedure because you can do the same with 1 simple select statement:

SELECT  SUM(Principal) as TotalPrincipal, SUM(Interest) as TotalInterest FROM RecordTrans

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Maybe you also need some filter in a WHERE clause unless you really want to sum the entire table.

mainrotor

ASKER

ScottPletcher,
I changed my code to SET @TOTALPRINCIPAL = @TOTALPRINCIPAL + @PRINCIPAL

But when I do the SELECT at the end
SELECT @TOTALPRINCIPAL AS TotatPrincipal
GO

I just get a NULL.

Why is that?

SOLUTION

Zberteoc

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ASKER CERTIFIED SOLUTION

Scott Pletcher

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