MySQL or JPQL query for getting different values from OneToMany relation

I have a table products which contains information like

id	product_name	retailer_name
1	Shirt	Gucci

This table has a OneToMany connection with product_prices which contains information like

id	price	country	product_id
100	95.5	United Kingdom	1
101	97.5	France	1
300	70.9	EUROPEAN_UNION	1

I need to create an MySQL or JPQL query which will retrieve

1. product_name
2. retailer_name
3. price (according to country or else choose European Union)

So for example: In case country United Kingdom is chosen -> then it will retrieve:

1. Shirt Gucci 95.5

In case country Italy is chosen -> then it will retrieve:

1. Shirt Gucci 70.9

As you can remark, in the second example, system retrieved EUROPEAN_UNION price because Italy could not be found.

In case country EUROPEAN_UNION is chosen -> then it will retrieve:

1. Shirt Gucci 70.9

As you can remark, in the third example, system retrieved EUROPEAN_UNION price because EUROPEAN_UNION country was found.

How can I achieve that ?

I have in tried in JPQL something like :

select new com.ProductDTOWithPrice(p.id, p.product_name, p.retailer_name, " +
        "pr.price) " +
        "from Product p " +
        "join ProductPrice pr " +
        "where p.id =:productId and (case when pr.country=:country then 1 " +
        "else when pr.country.id = EUROPEAN_UNION then 1 end)"

Also, tried to make multiple selects or use exists, but still, I can not figure it out. I am getting stuck on retrieving ''price''

Any help please ?