SQL Year over year growth percentage from data same query - sql

Question

How do I calculate the percentage difference from 2 different columns, calculated in that same query? Is it even possible?
This is what I have right now:
SELECT
Year(OrderDate) AS [Year],
Count(OrderID) AS TotalOrders,
Sum(Invoice.TotalPrice) AS TotalRevenue
FROM
Invoice
INNER JOIN Order
ON Invoice.InvoiceID = Order.InvoiceID
GROUP BY Year(OrderDate);
Which produces this table
Now I'd like to add one more column with the YoY growth, so even when 2016 comes around, the growth should be there..
EDIT:
I should clarify that I'd like to have for example next to
2015,5,246.28 -> 346,15942029% ((R2015-R2014) / 2014 * 100)

Answer 1

If you save your existing query as qryBase, you can use it as the data source for another query to get what you want:
SELECT
q1.Year,
q1.TotalOrders,
q1.TotalRevenue,
IIf
(
q0.TotalRevenue Is Null,
Null,
((q1.TotalRevenue - q0.TotalRevenue) / q0.TotalRevenue) * 100
) AS YoY_growth
FROM
qryBase AS q1
LEFT JOIN qryBase AS q0
ON q1.Year = (q0.Year + 1);
Access may complain it "can't represent the join expression q1.Year = (q0.Year + 1) in Design View", but you can still edit the query in SQL View and it will work.

Answer 2

What you are looking for is something like this?
Year Revenue Growth
2014 55
2015 246 4.47
2016 350 1.42
You could wrap the original query a twice to get the number from both years.
select orders.year, orders.orders, orders.revenue,
(select (orders.revenue/subOrders.revenue)
from
(
--originalQuery or table link
) subOrders
where subOrders.year = (orders.year-1)
) as lastYear
from
(
--originalQuery or table link
) orders
here's a cheap union'd table example.
select orders.year, orders.orders, orders.revenue,
(select (orders.revenue/subOrders.revenue)
from
(
select 2014 as year, 2 as orders, 55.20 as revenue
union select 2015 as year, 2 as orders, 246.28 as revenue
union select 2016 as year, 7 as orders, 350.47 as revenue
) subOrders
where subOrders.year = (orders.year-1)
) as lastYear
from
(
select 2014 as year, 2 as orders, 55.20 as revenue
union select 2015 as year, 2 as orders, 246.28 as revenue
union select 2016 as year, 7 as orders, 350.47 as revenue
) orders