Re: Help with UPDATE

This is no school work. I changed the table names and the column names to prevent using my company's table names. I graduated from college 12 years ago, this is not school work. I don't need hints, I'd appreciate a clear answer.

Enrique

DA Morgan <damorgan_at_x.washington.edu> wrote in message news:<1099976828.313511_at_yasure>...
> Enrique wrote:
>
> > I have two tables like these:
> >
> > Customer_Table
> > ----------------------------
> > Name Varchar2(20)
> > Address Varchar2(20)
> > Telephone Number
> > Price Number
> > Final_Price Number
> >
> > Discount_Table
> > -----------------------------
> > Name Varchar2(20)
> > Address Varchar2(20)
> > Telephone Number
> > Discount Number
> >
> > I want to update the Final_Price column in the Customer table by
> > joining both tables by Name, Address and Telephone and multiplying
> > Price with Discount.
> >
> > I tried:
> >
> > Update Customer_Table a
> > set a.final_price = a.price * (select b.discount from discount_table b
> > where a.name = b.name and
> > a.address = b.address and
> > a.telephone = b.telephone)
> >
> > This query was running for a long time and I killed it. I also suppose
> > this query will update ALL rows in the Customer_Table with the same
> > value since there is no WHERE clause in the Update.
> >
> > How can I do this??!!
>
> As this is school work here are two hints.
>
> 1. Your WHERE clause limits the rows selected but does not limit the
> rows updated.
>
> 2. What indexes exist on these tables?
Received on Tue Nov 09 2004 - 07:31:06 CST