I sell unit or a package of 20 unit, How can I control the Stock by Attribute?

[weber]

Same Question asked before by me. But I didn't understood....

For me, Item Price is $0
I add a Option Name:
Package
Under this, add Option Value
Each $2.00
20/CS $20.00
30/CS ..
50/CS ...
100/CS $200.00

Each item will be available in Single Unite or Case of 20/30--depend on item's original packge.

What I want, when customer select each, my stock will be deducted by 1. When order 20, will be deducted by 20, not one.

I can only find that there is a Price Offset there, and qty discount. but no qty offset or something.

Zen-cart Version 1.3.7

[gjh42]

To work correctly, you will have to use the quantity discount method. The attribute list as you show it will unfortunately not work right, although it looks better.

You can set the product to be available only in multiples, but then it will not be available as a single, and you can't specify 20 or 30 but not 10...

What might solve your problem is turning the quantity box from a text input to a dropdown or radiobutton, which could be pre-filled with only the values you want to allow. This will require some coding knowledge, but will probably be easy for someone who does have the knowledge.