Join conditions

[Former Member]

Hi ,

i have a small questions.

will join conditions in sql queries affect perfomance? how? give with an example

[Former Member]

Hi Vasanth,

You may have said the answer. But how will you know when you are writing a report whether it has large or small amount of data while writing a program for implementation Project. We will not all have any data for checking the performance. Ok . tell me something other than this if you know.

[Former Member]

Hi,

Look at the below link, you will get the correct information

http://blogs.ittoolbox.com/sap/db2/archives/for-all-entries-vs-db2-join-8912

Regards

Sudheer

[Former Member]

hi raju,

<b>join's</b> will affect the performance,

instead of this u can use <b>for all entries</b>.

reward points if helpful,

regards,

seshu.

[Former Member]

Hello,

<b>

Join  -  Used when the data in the table is less.

For all entries - Used when the data in the table is huge.

</b>

So use like this.

Vasanth

[Former Member]

hi,

deffinetly it will affects the perfomace.

<b>it will improves the perfomance when using view insted of using multiple select statements.

When multiple SAP tables are logically joined, it is always advisable to use inner join to read the data from them. This certainly reduces the load on the network.</b>

but we can improve the perfomance by using FOR ALL ENTRIES insted of using VIEWS .

regards,

Ashokreddy.

[Former Member]

check this:

<a href="/people/rob.burbank/blog/2007/03/19/joins-vs-for-all-entries--which-performs-better">JOINS vs. FOR ALL ENTRIES - Which Performs Better?</a>

Rob

[Former Member]

HI

Join will definetly affect ur performance.. Instead of this use For all entries.

Procedure.

Select all fields from one table and put it into one internal table.

then select fields from 2nd table using for all entries and put into another table.

This will reduce ur performance.

Reward me if its useful

Regards

Ravi

[Former Member]

Hi Vasanth,

You may have said the answer. But how will you know when you are writing a report whether it has large or small amount of data while writing a program for implementation Project. We will not all have any data for checking the performance. Ok . tell me something other than this if you know.

[Former Member]

The short answer is that it doesn't matter that much. Either method will give adequate performace. It's <b>far</b> more important to make sure you are using an index properly.

Rob

[Former Member]

answered