?
Solved

calculation in select

Posted on 2006-06-21
7
Medium Priority
?
1,435 Views
Last Modified: 2008-01-09
In sql server 2000 I have the following query in a stored procedure:
select  amount,
      amount * VAT / 100 as vatsum,
      amount + (amount * VAT / 100) as total
from table1

1. if the value of VAT is 0 then the value of total also become 0 although it is not 0 because it suppose to add the  
    amount. What is the problem here.
2. I wanted to write it like this
select        amount,
      amount * VAT / 100 as vatsum,
      amount + vatsum  as total
from table
but it is not accepted . what is the problem and how do I write it so that I write the calculation of vatsum only once?
Thankyou
Anat
0
Comment
Question by:ANAT2403
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
7 Comments
 
LVL 143

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 16952040
select  amount,
     amount * (VAT / 100) as vatsum,
     amount + (amount * (VAT / 100)) as total
from table1
0
 
LVL 5

Expert Comment

by:MageDribble
ID: 16952086
Whether you write is as "amount + vatsum" or "amount + (amount...."  It would still calculate vatsum twice b/c vatsum is just an alias to that column.  SQL Server would need to calculate it twice.

you could re-write it to eliminate the multiple calculations.  Try the below query and see if it returns faster results.

select  amount,
     amount * VAT / 100 as vatsum,
     amount + (amount * VAT / 100) as total
from table1
where amount <> 0

UNION ALL select  0,
                           0,
                           0
from table1
WHERE amount = 0
0
 
LVL 5

Expert Comment

by:MageDribble
ID: 16952102
if amount is indexed you may return faster results this way.
0
Get MongoDB database support online, now!

At Percona’s web store you can order your MongoDB database support needs in minutes. No hassles, no fuss, just pick and click. Pay online with a credit card. Handle your MongoDB database support now!

 

Author Comment

by:ANAT2403
ID: 16952533
nobody solved  the problem. the problem is not the fast of the query but that the total return 0 althogh in consists of
the amount which is not 0 and the vatsum which is 0
Can you help?
Anat
0
 

Author Comment

by:ANAT2403
ID: 16952632
Ok  sorry, I found it. it's my mistake .
actually the VAT was written like this:
ISNULL(VAT, 0) and I didn't write it in the second part.
Sorry
Thankyou all
Anat
0
 
LVL 5

Accepted Solution

by:
rmacfadyen earned 1500 total points
ID: 16952694
Are you certain of your problem? With a VAT of 0 there I would be hugely surpised if the total as zero (amount + (amount * 0 / 100)). Here's a hardcoded sample that shows the basic math works as expected:

declare @Amount decimal(8,2)
declare @Vat int

set @Amount = 10.23
set @Vat = 7

select @Amount, round(@Amount * @Vat / 100, 2), round(@Amount + (@Amount * @Vat / 100), 2)

set @Amount = 10.23
set @Vat = 0

select @Amount, round(@Amount * @Vat / 100, 2), round(@Amount + (@Amount * @Vat / 100), 2)

Are you perhaps not showing your full query? If you are not... have you considered how NULL will affect numeric calculations (SUM() and so forth)?

Regards,

Rob
0
 

Author Comment

by:ANAT2403
ID: 16952767
Thankyou you are write as you can see in my previuos answer I didn't show the complete query and there was the
problem that I already solved.
Anat
0

Featured Post

Percona Live Europe 2017 | Sep 25 - 27, 2017

The Percona Live Open Source Database Conference Europe 2017 is the premier event for the diverse and active European open source database community, as well as businesses that develop and use open source database software.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

International Data Corporation (IDC) prognosticates that before the current the year gets over disbursing on IT framework products to be sent in cloud environs will be $37.1B.
This article shows gives you an overview on SQL Server 2016 row level security. You will also get to know the usages of row-level-security and how it works
Via a live example, show how to backup a database, simulate a failure backup the tail of the database transaction log and perform the restore.
Viewers will learn how the fundamental information of how to create a table.
Suggested Courses

765 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question