From: Marcus, Operations Director
Subject: Are returns getting worse?
The warehouse team says they're handling more returns than ever. Before we change anything, I want the facts from RIDGELINE.SALES: how many orders come back, whether it's rising, and where it's concentrated. An order's STATUS is returned when it came back. Cancelled orders never shipped, so leave them out of every rate.
A case study is closer to real work than a lesson: one question, several queries that each answer part of it, and a judgement at the end. Each step is checked, so you'll know your numbers are right before you draw a conclusion from them.
Keep the definitions consistent across steps. The return rate is returned orders divided by orders that shipped (every status except cancelled). Round rates to 3 decimal places.