sqlrevenue

SQL: How to return revenue for specific year


I would like to show the revenue for a specific year for all customers regardless of whether or not they have revenue data for the specific year. (in cases they dont have data for the specific year, a filler like 'no data' would work)

Sample Data looks like:

Table 1

Customer Price Quantity Order Date
xxx 12 5 1990/03/25
yyy 15 7 1991/05/35
xxx 34 2 1990/08/21

Desired Output would look a little something like this:

Customer Revenue (for 1990)
xxx 128
yyy no data

Getting the total revenue for each would be:
SELECT Customer,

SUM(quantity*price) AS Revenue

but how would i go about listing it out for a specific year for all customers? (incl. customers that dont have data for that specific year)


Solution

  • We can use a CTE or a sub-query to create a list of all customers and another to get all years and the cross join them and left join onto revenue. This gives an row for each customer for each year. If you add where y= you will only get the year requested.

    CREATE TABLE revenue(
    Customer varchar(10),
    Price int,
    Quantity int,
    OrderDate date);
    
    insert into revenue values
    ('xxx',   12,5,'2021-03-25'),
    ('yyy',   15,7,'2021-05-15'),
    ('xxx',   34,2,'2022-08-21');
    
    with cust as 
    (select distinct customer c from revenue),
    years as
    (select distinct year(OrderDate) y from revenue)
    select 
    y "year",
    c customer ,
    sum(price*quantity) revenue
    from years 
    cross join cust 
    left join revenue r
    on cust.c = r.customer and years.y = year(OrderDate)
    group by 
    c,y,
    year(OrderDate)
    order by y,c
    
    year | customer | revenue
    ---: | :------- | ------:
    2021 | xxx      |      60
    2021 | yyy      |     105
    2022 | xxx      |      68
    2022 | yyy      |    null
    

    db<>fiddle here