关于我的关系数据库查询的建议

Hi I have just started using relational databases at college and I am having trouble with queries when using multiple tables. I normalized some data to the best of my knowledge as you can see below, however I am unsure how to write a query which will show me all of the products a particular customer has bought. When I have tried it just shows me all products along with that 1 customer even if they have not bought anything. Many thanks in advance!Hi I have just started using relational databas