Anyone Here Know Sql?

I am having a problem with an SQL query. This is my original table definition in IBM DB2:

Code:

---

CREATE TABLE Book
(
        BookID  INTEGER NOT NULL,
        Title  VARCHAR(50) NOT NULL,
        Price  DECIMAL(10,2) NOT NULL,
        CategoryID        INTEGER,
        PublisherID        INTEGER,
        CONSTRAINT PrimaryKey PRIMARY KEY
        (
          BookID
        )
);

---

That works fine, but now I want to write a query which will make a discount on all the books which have a certain CategoryID.
For example, implement a discount of 10% on all books in categoryID 1:

Code:

---

CREATE VIEW DiscountView AS SELECT BookID, Title, Price, CategoryID, PubliserID, Price/10 AS Discount FROM Book WHERE Book.CategoryID = 1;
SELECT * FROM DiscountView WHERE Book.CategoryID = 1;
UPDATE Book SET Price = Price - Discount WHERE Book.CategoryID = 1;

---

The Update statement is where it all goes wrong - I get an error message saying:
DB21034E The command was processed as an SQL statement because it was not a
valid Command Line Processor command. During SQL processing it returned:
SQL0206N "DISCOUNT" is not valid in the context where it is used.
SQLSTATE=42703


Does anyone know how I can get it to work? It has to take a percentage value, because later I will write a Java Database Connectivity program whereby a user will specify a percentage value, to discount all the books in a specific category.

Thanks for any help. ;)

google. :lol:

or a linux help forum (found on google) :P

OK, I've found my way to http://www.linuxquestions.org/ forum and posted my problem on there.
I hope someone there will know, as this has to be in tomorrow. Although it doesn't matter too much - this is only one small part of the task, and I've done nearly everything else. :)

have you declared discount somewhere and have you called it in the from statement.


im doing sql at the minute so im still learning.