SQL NULL Handling

SQL NULL handling refers to the techniques and functions used to manage NULL values in SQL databases, where NULL represents missing, unknown, or inapplicable data. It involves understanding how NULL behaves in comparisons, aggregations, and joins, and using specific operators and functions to handle these cases effectively. Proper NULL handling is crucial for accurate query results and data integrity in relational databases.

Also known as: NULL management, NULL values in SQL, SQL NULL operators, Handling missing data in SQL, IS NULL / IS NOT NULL

Why learn SQL NULL Handling?

Developers should learn SQL NULL handling to avoid common pitfalls like incorrect query results or errors when dealing with incomplete data, such as in data analysis, reporting, or application logic that interacts with databases. It is essential in scenarios like filtering data with WHERE clauses, performing calculations with aggregate functions, or merging datasets with joins, where NULL values can lead to unexpected behavior if not managed properly.

Learning Resources

• tutorial: SQL NULL Values - W3Schools
• docs: Handling NULL Values in SQL - PostgreSQL Documentation
• tutorial: SQL NULL Handling Explained - freeCodeCamp
• course: Mastering NULL in SQL - Coursera Course
• video: SQL NULL Functions: COALESCE and NULLIF - YouTube Tutorial