topic Re: Performing multiple joins on table in Application Development and Automation Discussions

Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 12:09:22 GMT

Hi all,

I would like to know if performing joins on more than 10 tables has some performance issues? If so, is there any limit on the joins that can be done?

Is there another way out for this problem?

Re: Performing multiple joins on table

Sandeep_Panghal — Thu, 11 Dec 2008 12:13:14 GMT

Hi,

There is no limit as such to use number of joins but if you have 10 tables(with huge data) obviously you will run into performance issues.

Better use join on 2-3 tables and then do your operations on the internal tables.

Rgds,

Sandeep

Re: Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 12:13:35 GMT

HI,

Refer to this link...

Re: Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 12:21:57 GMT

There can be a maximum of 24 "JOIN" joining 25 Tables or views.

Performance issue will depend on the fields used for restricting data.

There is no problem in Joining 3 or more tables your where clause should be covering the important fields.

Re: Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 14:59:19 GMT

Hi,

If you are talking about performance then always use for all entries.

Thanks & Regards,

Krishna..

Re: Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 15:14:57 GMT


> There can be a maximum of 24 "JOIN" joining 25 Tables or views.

Can you show where this is documented?

Rob

Re: Performing multiple joins on table

ThomasZloch — Thu, 11 Dec 2008 16:07:40 GMT

F1-Help for JOIN (in Rel. 7.00). Coincidentally I just found that today and learned about that limit. It will be difficult to get close to this limit in a reasonable fashion though...

Thomas

Re: Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 16:12:49 GMT

I'm a bit embarassed - I looked at that as well and missed it.

I wonder if that limit would include the tables that are included in the views.

Rob

Re: Performing multiple joins on table

ThomasZloch — Thu, 11 Dec 2008 16:21:52 GMT

If I had to bet, I'd say no, not included...do you have time to try out with a little test program?

Re: Performing multiple joins on table

JozsefSzikszai — Thu, 11 Dec 2008 16:22:14 GMT

If you are talking about performance then always use for all entries.

I wonder, if we can have a thread once, without this statement...

Re: Performing multiple joins on table

Former Member — Thu, 11 Dec 2008 16:36:06 GMT


> If I had to bet, I'd say no, not included...do you have time to try out with a little test program?

Probably not so little, but maybe sometime. I know there are standard SAP views with upwards of 13 or 14 tables, but I doubt if they would be compatable for joining.

Rob

Re: Performing multiple joins on table

Former Member — Mon, 15 Dec 2008 14:38:17 GMT

Hi,

You can uase joins rather than nested loops....

Up to three joins are okey, more joins degrade performance....

Better practice is to use for all entries....

Thanks & Regards,

Krishna...

Re: Performing multiple joins on table

Former Member — Mon, 15 Dec 2008 14:44:47 GMT

> >


> > If I had to bet, I'd say no, not included...do you have time to try out with a little test program?

> Probably not so little, but maybe sometime. I know there are standard SAP views with upwards of 13 or 14 tables, but I doubt if they would be compatable for joining.

> Rob

How about a self join?

Re: Performing multiple joins on table

Former Member — Mon, 15 Dec 2008 14:50:35 GMT

> How about a self join?

Sounds OK - what are your results?

Rob