How to create and differentiate between 3 choices using TinyINT in MySql

How to create and differentiate between 3 choices using TinyINT in MySql

I have a Product Table that has isAvailable field which is set to true if
it is available and false if it is not.
Order Table Fields:
orderID, productID, productName
Product Table Fields:
productID, productName, isAvailable
Now I am thinking to create another table called Order which allows a
product to be ordered so how can I change the isAvailable field so that it
will take 3 choices and I was wondering how I can incorporate this into
the Product table.
Would this involve some sort of IF() condition in the Product Table when
creating it??
Any help would be appreciated.