Data Deduplication with DISTINCT
Welcome to this SQL lab! Here, you'll test and hone your SQL skills using the Chinook
dataset and the SQLite database system.
Dataset Overview:
The Chinook dataset emulates a digital media store, containing tables related to albums, artists, tracks, invoices, and more.
Here are some key tables you'll be working with:
"Artist"
: Contains artist details."Album"
: Holds information about each album, linked to artists."Track"
: Details about individual tracks, their genres, media types, and the albums they belong to."Customer"
: Data about customers."Invoice"
: Billing information for purchases made by customers.
Environment:
- This lab utilizes SQLite. Ensure you're familiar with its syntax and functionalities.
- Make sure to stick to the exact names for tables and columns as defined in the Chinook database schema.
- Always use double quotes for column and table names for clarity.
Challenges:
Your main task is to complete a set of SQL challenges. Each challenge will test a specific aspect of SQL, and you're expected to write SQL queries to fetch, analyze, or manipulate data from the Chinook dataset.
Objective:
Retrieve the most recent invoice date for every customer in the Chinook database.
Tables Used:
Customer
Invoice
Instructions:
- Join the
Customer
table with theInvoice
table using the appropriate key. - For each customer, determine and select the most recent invoice date.
- Your result should display the following columns:
CustomerId
MaxInvoiceDate
(this should be an alias for the latest invoice date for clarity)
Output Specifications:
-
Columns:
CustomerId
MaxInvoiceDate
-
Order:
- The results should be ordered by
CustomerId
in ascending order.
- The results should be ordered by
Hint:
Consider using aggregation functions and grouping to achieve the desired result. Ensure all columns are named accurately as described to pass the evaluation.
Notes:
- Carefully read each challenge's description. Pay close attention to the expected output and the order of results.
- Always ensure that your SQL queries match the specified requirements to pass the evaluation.