Week 2 · SQL Fundamentals
Week 2: Asking Questions with SQL
SQL lets you ask questions of databases directly. This week introduces databases, tables and records, then the handful of SQL clauses that answer most business questions. It is a practical introduction, not database engineering.
Learning objectives
- Understand databases, tables and records
- Select and filter data with SELECT and WHERE
- Sort results with ORDER BY
- Summarize with GROUP BY, COUNT, SUM and AVG
- Understand the basic idea of joining two tables
- Translate a business question into a simple query
-- Which categories earn the most?
SELECT category,
SUM(order_total) AS revenue
FROM orders
WHERE order_date >= '2026-01-01'
GROUP BY category
ORDER BY revenue DESC;
Practical skills
- Reading table structures
- SELECT and WHERE
- ORDER BY
- GROUP BY
- COUNT, SUM, AVG
- Basic JOIN concepts
- Practical business queries
Business examples
Questions you will answer
- How many orders did we receive each month?
- Which five customers spent the most this year?
- What is the average order value by product category?
Practical business case
Explore customer and order data. You will query a sample store database to find top customers, revenue by category and order trends over time.
Weekly assignment
Write basic SQL queries to answer a list of business questions, and record each answer in a short table with one sentence of interpretation.