SQL question

[Sims, John]

> -----Original Message-----
> From: valentina-bounces at lists.macserve.net 
> [mailto:valentina-bounces at lists.macserve.net] On Behalf Of 
> Florian Bogeschdorfer
> Sent: Tuesday, November 29, 2005 2:33 PM
> To: 'Valentina Developers'
> Subject: SQL question
> 
> Hi all!
> 
> Say I have two tables:
> 
> TABLE CUSTOMER with fields ID,NAME,ADRESS
> 
> And
> 
> TABLE PAYBACKCARD with fields CUSTOMER_ID,ID,CARDNUMBER
> 
> If I search for customers with cards, I do "SELECT * FROM 
> CUSTOMER,PAYBACKCARD WHERE CUSTOMER.ID=PAYBACKCARD.CUSTOMER_ID"
> 
> Fine. But now I want to find all customers WITHOUT card. How 
> can I do this?
> In this case there is no link between the two tables, I need 
> "SELECT * FROM CUSTOMER WHERE there is no link between the tables..."
> 
> TIA
> 
> Florian
> 

Hi Florian,

I'm not 100% sure that Valentina supports this, but the most common way
I know of would be...

SELECT * FROM Customer WHERE NOT Customer.ID IN (SELECT Customer.ID FROM
Customer,PaybackCard WHERE Customer.ID=PaybackCard.Customer_ID)

If that doesn't work, look into the EXISTS keyword of SQL.

Good luck.

-John