How to use where clause in JPQL?

Question

I made a shopping cart web application for a stores. If a customer log into the system, They are adding some items to there shopping cart. In my case, I store that all cart items in table named, ShoppingCart. I have 2 tables named, Customer and ShoppingCart. ShoppingCart primary key is userName. userName is a attribute of Customer table. I need to get all the ShoppingCart entries where userName.

SELECT o FROM ShoppingCart o, Customer c WHERE c.userName = :id

id is the primary key of ShoppingCart. I failed to get correct result from this query. How can I do it?

Thanks in Advance.

Answer 1

You can try the below query. In your query, you haven't added which column should be joined to fetch exact results for the given id.

SELECT o FROM ShoppingCart o, Customer c WHERE c.userName = o.userName AND o.userName = :id

Also, you can try adding relationships one-to-many as each customer can have one or more than that order items.

SELECT c FROM Customer c JOIN c.orders o WHERE c.userName = :id

Here, orders is the collection of orders for particular customer. Then from Customer, you can get its orders.