Hope all is well. I am trying to build SQL query which pulls order value of a customer and the order value of same quarter but of prior year from the same customer. Can someone please explain the SQL format with an example I should follow?
For example- There are three tables i.e. A(customer data), B(order quantity), C (order amount) Each table has a common key 'keycutomer'-serial number of each customer.
Now I want to pull what is the order value and quantity of Mr. A in 4Q2017 and 4Q2016.