All Articles - Simplify Database

SQL Constraints Explained Simply: NOT NULL, UNIQUE, CHECK and DEFAULT

Learn how SQL constraints like NOT NULL, UNIQUE, CHECK and DEFAULT protect your data, with simple examples you can use right away.

A practical guide to SQL data types: numbers, text, dates and more, with differences between SQL Server, MySQL and PostgreSQL.

A beginner-friendly guide to SQL window functions: OVER, PARTITION BY, ROW_NUMBER, RANK, running totals and LAG, with clear examples.

Learn what stored procedures are, how to create and run them in SQL Server, MySQL and PostgreSQL, and when they are worth using.

Learn what a SQL view is, how to create one, and how views simplify queries, improve security and keep reports consistent.

What SQL transactions are, how BEGIN, COMMIT and ROLLBACK work, and what ACID means, explained with a simple bank transfer example.

Learn how to add, change and remove data in SQL with INSERT, UPDATE and DELETE, plus the safety habits that stop costly mistakes.

My pick of the best SQL and database books for every level, from your first query to database design, performance and large-scale data systems.

Understand the difference between SQL subqueries and CTEs (WITH clauses), when to use each, and how they affect readability and performance.

Learn what SQL indexes are, how they speed up queries, which columns to index, and when an index can slow you down.