Question

Recursive SQL Functions (Syntax)

Asked by: ApxMike

I have tried to create recursive fuctions with MS SQL 2000 and 2005, and have not been sucessfull.  I have tried numerous ways and examples from online, none of which have worked.

Below are two examples which do not work on either of my machines.  (the + sign doesnt show correctly).

If anyone has experience with recursive SQL procedures I would appreciate your assistance.

Thanks!

Attempt I wrote:
 
CREATE FUNCTION TestSum
(
	@i int,
	@sum int
)
RETURNS int
AS
BEGIN
	SET @sum = @sum + @i
 
	if (@i > 1) begin
		return TestSum(@i - 1, @sum)
	end
	else begin
		RETURN @sum
	end
END
 
 
 
 
 
Example from online:
create function RecursiveTest(@V int)
returns @t table (i int)
as
   begin
   set @v = @v - 1
   if @v<>0
     insert into @t 
     select @v union 
     select * from RecursiveTest(@v)
   else
     insert into @t values (0)
   return
   end
 
select * from RecursiveTest(10)
                                  
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:

Select allOpen in new window

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2008-12-22 at 22:29:31ID24005039
Tags

SQL Recursive Functions

Topics

MS SQL Server

,

SQL Server 2005

Participating Experts
5
Points
500
Comments
13

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. ColdFusion event calendar-recurring events
    Hi. I have been asked to create a ColdFusion application to track events for May-July. The events need to be searchable by users. The resutls page should display a calendar of the selected month with days with events highlighted. I have been working with ColdFusion for a ...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: Marekch84Posted on 2008-12-22 at 23:03:35ID: 23231793

The example from online works on my sql 2005, but still why you want recursive functions? If you will exceed the limit of 32 callings the function will be stoped and the transaction rolled back. There is a nesting limit of 32 callings.

 

by: Mortaza_doulatyPosted on 2008-12-22 at 23:13:39ID: 23231831

When calling User Defined Functions (UDF) you need to specify the schema owner, (dbo in default)

So you need to change your code to:

ALTER FUNCTION TestSum
(
        @i int,
        @sum int
)
RETURNS int
AS
BEGIN
        SET @sum = @sum + @i
 
        if (@i > 1) begin
            return dbo.TestSum(@i - 1, @sum);
		end
	
        RETURN @sum
        
END
 

                                              
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:

Select allOpen in new window

 

by: Marekch84Posted on 2008-12-22 at 23:49:39ID: 23231934

this is true but still in 2005, if the function is not in not found in users schema, sql tries to find the function in the dbo. If no schema is specified during creaction default user schema is used, so it should work even without schema specs.

 

by: Mortaza_doulatyPosted on 2008-12-22 at 23:58:00ID: 23231963

Just remove the dbo in line 12 and try to execute:

Msg 195, Level 15, State 10, Procedure TestSum, Line 12
'TestSum' is not a recognized built-in function name.


 

by: RacimoPosted on 2008-12-23 at 01:53:22ID: 23232352

<<If anyone has experience with recursive SQL procedures I would appreciate your assistance>>
User Defined Functions are not meant for this kind of use. Instead , use Assemblies.  

Also be aware that recursive reasonning on a DBMS can be a serious performance killer especially when using temp tables. Keep in mind that you are doing IO's from disks (namely tempdb) and not IO from RAM.

If you could post more details on what you are trying to accomplish, we may suggest an alternative.

HTH

 

by: chapmandewPosted on 2008-12-23 at 04:07:56ID: 23232923

>>User Defined Functions are not meant for this kind of use.
Actually, you can use UDFs recursively in 2005...which is kinda neat.

In reality though, if you're trying to do recursion in 2005, you're better off using a recursive CTE.  Here is an article I wrote on how to do it:
http://blogs.techrepublic.com.com/datacenter/?p=275

 

by: RacimoPosted on 2008-12-23 at 04:40:11ID: 23233100

<<Actually, you can use UDFs recursively in 2005...which is kinda neat. >>
Nobody said that he could *not* do it through UDF but simply that it is not recommended perfomance wise.

<<In reality though, if you're trying to do recursion in 2005, you're better off using a recursive CTE. >>
Whether through CTE or through functions or through stored procedures, recursion is a performance killer.

 

by: chapmandewPosted on 2008-12-23 at 04:45:39ID: 23233127

Recursion is going to be slow through the CLR as well...especially if you're recursing through a lot of records.

 

by: RacimoPosted on 2008-12-23 at 04:49:13ID: 23233149

<<Recursion is going to be slow through the CLR as well...especially if you're recursing through a lot of records.>>
True but from experience, it is the least worst of all solutions.  this is why I asked the questionners to tell us more to see if we could do it without recursion.
Regards...

 

by: ApxMikePosted on 2008-12-23 at 08:42:45ID: 23234746

As part of a project I am working on there are formulas and variables which the user can specify.  Both are stored in a DB.  Right now I querry the information and then on the desktop application I evaluate the formulas.

Everything works just fine, the problem is that my boss wants to be able to call a stored procedure manually to evaulate the return value of a formula.  I.E.  Open Query Analyzer and type in a query.

He wants to be able to verify that this small piece of the program (because it is a very important piece) works correctly.

There are two steps that need to be done:
1. Substitute all the variables for their correct value from a DB table.
2. Evaluate the mathematical expression.

Thank you for your assistance.
 

 

by: RacimoPosted on 2008-12-23 at 10:55:18ID: 23235654

<<Thank you for your assistance.>>

Could you provide an example based on the two steps you provided.  Thanks.

 

by: ApxMikePosted on 2008-12-23 at 11:39:14ID: 23235976

These formulas are part dependent.  I.E.  The same formula returns a different value depending on the part used.

Some variables are fixed independent of the part - such as labor.  Other variables depend on the cost of the material or length of time required.

A Formula might be:      Labor+2.5*WheelCost/PartsPerWheel
but could be more complex.

After substitution let's say it is  7.8+2.5*6/8
Then it is simple math.

 

by: Sharath_123Posted on 2009-01-11 at 16:45:55ID: 23350438

-- create the function like this
CREATE FUNCTION TestSum
(	@i int,	@sum int)
RETURNS int
AS
BEGIN
	  SET @sum = @sum + @i
    if (@i > 1) begin set @sum = dbo.TestSum(@i - 1, @sum) end
		RETURN @sum
end
 
-- execute the function. it returns 25 for i = 5, sum = 10 i.e. (5+4+3+2+1) + 10 = 25
select dbo.testsum(5,10)

                                              
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:

Select allOpen in new window

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...