topic Re: Using Select Aggregate Statements in Application Development and Automation Discussions

Using Select Aggregate Statements

former_member207873 — Mon, 15 Sep 2014 13:20:29 GMT

Hi Experts,

I am getting mixed response regarding the use of aggregate statements in select query. My concerns are:

1) Using aggregate function in select query or processing in internal table is more efficient ?

2) If it is database dependent (as some may argue ), for which databases we have to use aggregate function and for which we should avoid to use it ?

3) Is there any relevant study regarding this topic, I mean some statistics with the no of records, and the underlying database used.

Sam.

Re: Using Select Aggregate Statements

former_member207873 — Tue, 16 Sep 2014 05:02:37 GMT

Any inputs on this ?

Re: Using Select Aggregate Statements

aarif_baig — Tue, 16 Sep 2014 05:18:26 GMT

Hi Sam,

It really depends on volume of data and requirement, what i would recommend is to process the internal table instead of using aggregate, most of the time you would be using some kind of loop after select for manipulating data so what you are trying to achieve can easily be achieved in the existing loop and keep select query simple. but again it depends on requirement

Thanks

Re: Using Select Aggregate Statements

Former Member — Tue, 16 Sep 2014 11:31:02 GMT

Hi Sam,

I agree with Aarif, but you can make use of aggregate functions while writing select query rather than using loops on internal tables to find Max. Value for example as this is more efficient.

Please refer to the link below for more information on Aggregate statements.

ABAP Keyword Documentation

Regards,

Ashvin

Re: Using Select Aggregate Statements

former_member207873 — Tue, 16 Sep 2014 11:37:47 GMT

Hi Ashvin,

But my question is when and where to use aggregate functions since we can do all the functions performed in an aggregate statement inside internal table loop. If using aggregate functions have perform problem why do they exist ?

Re: Using Select Aggregate Statements

Former Member — Tue, 16 Sep 2014 11:50:50 GMT

This message was moderated.

Re: Using Select Aggregate Statements

UweFetzer_se38 — Tue, 16 Sep 2014 12:31:54 GMT

Hi Sam,

I don't know where you found this nonsense, but the rule of thumb is: don't transport (DB -> Application Server) data if you don't need it. Means: if you just need the maximum value or a sum of a database query why you want to read and transfer all the data to the application server?

Let do the DB do all the work for you, especialy if it's already a HANA installation.

Re: Using Select Aggregate Statements

former_member207873 — Tue, 16 Sep 2014 12:42:24 GMT

Hi Fetzer,

Thanks for your answer. But just have a look on to the answers I received, they are not appreciating the use of aggregate statements. Many of my colleagues also belong to the school of thought that using aggregate statements will have performance problems. So what I have to take ?

Re: Using Select Aggregate Statements

UweFetzer_se38 — Tue, 16 Sep 2014 12:51:18 GMT

And noone has explained WHY they believe it is so yet, because it's not possible...

So what I have to take

Just think about arguments pro and contra. I already gave you some (unnecessary transfer of data).

Re: Using Select Aggregate Statements

aarif_baig — Wed, 17 Sep 2014 01:46:19 GMT

Hi Fetzer,

I just wrote blog on this may be you can share your thoughts

Regards,