SQLancer
Technical Blog

Database Insights & Engineering

Deep dives into indexing algorithms, query optimization, engine architecture, and schema design.

Featured Indexes 8 min read

How Database Indexes Actually Work Under the Hood

Ever wondered how a database retrieves records out of millions in milliseconds? Let's take an illustrated journey into B-Trees, Hash indexes, and scan patterns.

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Queries 5 min read

SQL Joins Explained Visually (With Interactive Examples)

Struggling to remember the difference between RIGHT JOIN and FULL OUTER JOIN? Interactive diagrams and Wasm query trials will clear it up once and for all.

Architecture 12 min read

PostgreSQL vs MySQL in 2026: Which One Should You Choose?

An unbiased feature comparison of the two giants in 2026, touching on JSON performance, ACID compliance, extension ecosystem, and setup speed.

Optimization 7 min read

5 Simple SQL Query Optimization Techniques for Production

Learn how to read EXPLAIN plans, avoid SELECT *, leverage index-only scans, and write faster query statements with real performance benchmarks.

Schema Design 10 min read

A Practical Guide to Database Normalization (1NF to 3NF)

Learn how to eliminate data redundancy and prevent data anomalies by structuring your database tables with practical real-world store examples.

Engineering 9 min read

Behind the Scenes: Running SQLite inside Wasm in the Browser

How we built our interactive Wasm sandbox allowing students to compile schema and run SQL statements in real time without a backend server.