Updating Column Data on the Fly?

[erikthenomad]

Hey...newbie question: I've got three columns in my database, the
third of which is blank right now, and I need it to equal the value of
column one minus column two. While I can accomplish this in the .aspx
page with a subroutine, I want to do it in SQL Server so I can simply
read the data in the page and not have to do any calculations. Help
please? Thanks.

Erik

[David Portas]

Best not to put the third column in the table. Just calculate the result in
a SELECT statement when you query the table:

SELECT col1, col2, col1-col2 AS col3,
FROM YourTable
WHERE ...

--
David Portas
SQL Server MVP
--

[erikthenomad]

Excellent. Thanks David.

Erik

[erikthenomad]

Another quick question -- if I want to SUM values in col1 WHERE a
certain condition exists before subtracting col2 from it, I run into an
"Aggregate function" error...is there a way around that?

[John Bell]

Hi

You probably want a subquery see the topic "Subquery Fundamentals" in Books
Online.

John

<er**********@hotmail.com> wrote in message
news:11**********************@c13g2000cwb.googlegr oups.com...

Another quick question -- if I want to SUM values in col1 WHERE a
certain condition exists before subtracting col2 from it, I run into an
"Aggregate function" error...is there a way around that?

[erikthenomad]

That did the trick. Thanks!

Erik