Question

I would like to create a sql query that returns results together for 2 different queries. For example, I’d like to have results in the form of:
Product Name, avg(price), min(price), max(price), avg(order), min(order), max(order)
At the moment I have 2 sql queries of the form:

select 
  product.name, order.id, avg(price), min(price), max(price) 
from 
  product, order 
where
  product.name = order.product_name and product.name = 'price' 
group by 
  product.name, order.id

select 
  product.name, order.id, avg(order), min(order), max(order) 
from 
  product, order 
where 
  product.name = order.product_name and product.name = 'order' 
group by 
  product.name, order.id

Some products have a price and an order, others have only a price, and others have only and order. How do I write a query that will display all the results and join those that have both an order and a price and display those that have both as i row?

Answer 1

I think what you need is a full outer join since rows could be in either one table or the other or both:

SELECT 
   NVL(t1.name,t2.name) as name,
   NVL(t1.id, t2.id) as id,
   avg_price,
   min_price,
   max_price,
   avg_order,
   min_order,
   max_order
FROM 
(select product.name, order.id, avg(price) as avg_price, min(price) as min_price, max(price) as max_price 
from product, order 
where product.name = order.product_name and product.name = 'price' 
group by product.name, order.id) t1
FULL OUTER JOIN
(select product.name, order.id, avg(order) as avg_order, min(order) as min_order, max(order) as max_order
from product, order 
where product.name = order.product_name and product.name = 'order' 
group by product.name, order.id) t2
ON t1.name = t2.name