SQL Tutorials

Learn how second normal form (2NF) can improve your database design by eliminating partial dependencies.

Learn the art of pivoting rows into columns in SQL in Oracle, MySQL, and SQL Server. Explore practical methods with detailed examples to boost your data engineering skills.

Understand how to use common table expressions to simplify complex queries for improved readability. Learn the difference between non-recursive and recursive CTEs.

Learn how third normal form (3NF) can help you organize your databases more efficiently by removing redundancy and minimizing dependency issues. See how decomposing tables can simplify data management.

Learn how to set up PostgreSQL on macOS using Homebrew, a convenient package manager. Follow step-by-step instructions to install, configure, and start PostgreSQL services.

Learn how to update multiple columns in SQL using a single query for improved efficiency. Explore practical advanced techniques and examples, including single row updates and multiple row updates.

Explore the different methods for filtering out and permanently removing duplicate rows using SQL. Learn the practical applications of how to remove duplicates in SQL Server, MySQL, and PostgreSQL.

Discover how WHERE filters row-level data in SQL queries, while HAVING filters grouped data after aggregation, and master their distinct uses in SQL querying.

Understand the SQL order of execution and how its different from the order of writing. Write accurate and optimized queries for improved performance and avoid common mistakes in query design.

A transitive dependency occurs when one attribute in a database indirectly relies on another through a third attribute, causing redundancy. Keep reading to learn how to identify and eliminate transitive dependencies in database design .

Learn how UPDATE with JOIN in SQL simplifies cross-table updates in SQL Server. Understand how INNER JOIN and LEFT JOIN differ for specific use cases, and explore alternatives using subqueries or the MERGE statement.

Explore how using a SQL alias simplifies both column and table names. Learn why using a SQL alias is key for improving readability and managing complex joins.