Blog
Tutorials, tips, and insights on SQL and business logic

How People Learn SQL: Patterns from 50,000+ Exercises
We analyzed over 50,000 exercise completions to find where SQL learners get stuck, what topics they avoid, and what separates beginners from advanced practitioners.

Best SQL Practice Websites in 2026
We tested eight popular SQL practice platforms and compared them on exercise quality, databases, cost, and ease of use. Here is what we found.

SQL Data Types: A Practical Reference for Beginners
Learn essential SQL data types — INTEGER, VARCHAR, NUMERIC, DATETIME, and BOOLEAN — with real Chinook database examples and a cheat sheet.

SQL Aliases Explained: AS for Tables and Columns
Learn SQL aliases with the AS keyword to rename columns and tables. Practical examples, a cheat sheet, and hands-on exercises using Chinook.

SQL ORDER BY and LIMIT: Sorting and Paging Results
Learn how to sort query results with ORDER BY and control output size with LIMIT and OFFSET. Master SQL pagination with practical Chinook database examples.

SQL CREATE TABLE and ALTER TABLE: DDL Essentials
Learn SQL CREATE TABLE and ALTER TABLE with practical examples. Master DDL to design, modify, and understand database table structures.

SQL CASE WHEN: Conditional Logic in Queries
Learn how to use SQL CASE WHEN to add conditional logic to your queries. Master simple and searched CASE expressions with practical Chinook database examples.

SQL BETWEEN, IN, and LIKE: Pattern Matching Guide
Master SQL pattern matching with BETWEEN, IN, and LIKE operators. Learn wildcard syntax, date ranges, and value lists with real Chinook database examples.

SQL NULL Handling: IS NULL, COALESCE, and IFNULL
Learn how SQL NULLs work and how to handle them with IS NULL, COALESCE, and IFNULL. Includes real Chinook database examples, result tables, and common mistakes to avoid.