I want to retrieve data from one row and where the fields are empty get the data from another row (with the same product_id). So here I want to get the data from row 3 but for all the fields that are empty get those from row 1:

product_id, v_id, name, summary, price
1, "1", "beans", "delicious and tasty", "10.00"
1, "2", "", "", "11.00"
1, "3", "fava beans", "", "12.00"
1, "4", "", "", "13.00"

select * from product where product_id='1' and v_id='3' (then if field='' get from v_id='1')

I hope that makes sense, thank you in advance.