SQL Year over year growth percentage from data same query

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