You're working for a company that sells motorcycle parts, and they've asked for some help in analyzing their sales data!
They operate three warehouses in the area, selling both retail and wholesale. They offer a variety of parts and accept credit cards, cash, and bank transfer as payment methods. However, each payment type incurs a different fee.
The board of directors wants to gain a better understanding of wholesale revenue by product line, and how this varies month-to-month and across warehouses. You have been tasked with calculating net revenue for each product line and grouping results by month and warehouse. The results should be filtered so that only "Wholesale" orders are included.
They have provided you with access to their database, which contains the following table called sales:
Sales
| Column | Data type | Description |
|---|---|---|
order_number | VARCHAR | Unique order number. |
date | DATE | Date of the order, from June to August 2021. |
warehouse | VARCHAR | The warehouse that the order was made from— North, Central, or West. |
client_type | VARCHAR | Whether the order was Retail or Wholesale. |
product_line | VARCHAR | Type of product ordered. |
quantity | INT | Number of products ordered. |
unit_price | FLOAT | Price per product (dollars). |
total | FLOAT | Total price of the order (dollars). |
payment | VARCHAR | Payment method—Credit card, Transfer, or Cash. |
payment_fee | FLOAT | Percentage of total charged as a result of the payment method. |
SELECT
product_line,
(CASE WHEN EXTRACT(month FROM date) = 6 THEN 'June'
WHEN EXTRACT(month FROM date) = 7 THEN 'July'
WHEN EXTRACT(month FROM date) = 8 THEN 'August' END) AS month,
warehouse,
ROUND((SUM(total) * (1 - payment_fee))::numeric,2) AS net_revenue
FROM sales
WHERE client_type IN ('Wholesale')
GROUP BY product_line, month, warehouse, payment_fee
ORDER BY product_line ASC, month ASC, net_revenue DESC;-- Comparing the net revenue from Wholesale clients across June, July and August
WITH table1 AS (
SELECT
EXTRACT(month FROM date)::int AS month_int,
(CASE WHEN EXTRACT(month FROM date) = 6 THEN 'June'
WHEN EXTRACT(month FROM date) = 7 THEN 'July'
WHEN EXTRACT(month FROM date) = 8 THEN 'August' END) AS month,
ROUND((SUM(total) * (1-payment_fee))::numeric,2) AS net_revenue
FROM sales
WHERE client_type = 'Wholesale'
GROUP BY month_int, month, payment_fee
ORDER BY month DESC)
SELECT
t1.month,
t1.net_revenue AS current_month_net_revenue,
t2.net_revenue AS previous_month_net_revenue,
(t1.net_revenue - t2.net_revenue) AS diff,
(CASE WHEN t1.net_revenue > t2.net_revenue THEN 'Increase'
WHEN t1.net_revenue < t2.net_revenue THEN 'Decrease'
WHEN t1.net_revenue = t2.net_revenue THEN 'Constant' END) AS trend
FROM table1 AS t1
LEFT JOIN table1 AS t2
ON t1.month_int = t2.month_int + 1
GROUP BY t1.month, t1.net_revenue, t2.net_revenue
ORDER BY month DESC