sql · beginner
Databases and SQL
Learn how real applications store and query data: tables, SELECT, JOINs, aggregates, and how to design a simple schema.
A beginner-friendly, practical tour of relational databases and SQL. You will learn what a database actually is, how tables/rows/columns/types work, how to read and write SELECT/WHERE/ORDER BY/LIMIT queries, how to safely INSERT/UPDATE/DELETE data, how relationships and foreign keys connect tables, how JOINs combine data visually, how GROUP BY and aggregates summarize data, why indexes matter for speed, and how to design a schema for a real small app.
Database Foundations
What databases are, how data is structured, and how to read data with SELECT and WHERE.
- What a Database Really IsLevel 1 · Complete beginner · Pass the quick check to continue12m
- Tables, Rows, Columns, and TypesFinish the lesson and pass the quick check in "What a Database Really Is" to unlock this lesson.13m
- SELECT and WHEREFinish the lesson and pass the quick check in "Tables, Rows, Columns, and Types" to unlock this lesson.14m
Shaping and Changing Data
Sorting, limiting, and safely inserting, updating, and deleting rows.
Connecting and Summarizing Data
Relationships, JOINs, aggregates, performance, and schema design for a real app.
- Relationships and Foreign KeysFinish the lesson and pass the quick check in "INSERT, UPDATE, DELETE Safely" to unlock this lesson.14m
- JOINs Explained VisuallyFinish the lesson and pass the quick check in "Relationships and Foreign Keys" to unlock this lesson.16m
- GROUP BY and AggregatesFinish the lesson and pass the quick check in "SELECT and WHERE" to unlock this lesson.14m
- Indexes and Why Queries Get SlowFinish the lesson and pass the quick check in "SELECT and WHERE" to unlock this lesson.13m
- Designing a Schema for a Real AppFinish the lesson and pass the quick check in "Relationships and Foreign Keys" to unlock this lesson.15m
- Design and Query a Bookings DatabaseComplete "Designing a Schema for a Real App" to unlock this project.~4h