SQL Syllabus
This course starts with reading a table, then moves into relationships, safe changes, schema design, and larger reports. You do not need a paid account or a prior database course to begin.
Understand the idea
Stage 1: practise SELECT, WHERE, ordering, NULL, and aggregates. Stage 2: join tables and explain the grain of a result. Stage 3: use constraints, parameters, and transactions to protect changes. Stage 4: build CTE and window-function reports, inspect query plans, and reconcile totals. Use the reference pages when syntax differs between engines rather than memorising every vendor function.
Where to try it
Run this example in the SQL playground. The lesson link loads the shop tables and sample rows before this query. Select Run when you are ready. Every run starts fresh, so your changes do not affect the website or a previous run.
SQLite sample data · MySQL / MariaDB sample data · See the sample tables
Your task
Choose one question for each stage and write what evidence would convince you that your answer is correct.
Show the worked solution
SELECT 'Read and filter' AS stage
UNION ALL SELECT 'Join and aggregate'
UNION ALL SELECT 'Model and change safely'
UNION ALL SELECT 'Analyse and tune';
Check your result
The script lists the four study stages. It is a small SQL example, not a tracking system. Your real progress is the ability to explain and test a query against a stated requirement.