Working with NULL Values in SQL

Learn what NULL values mean in SQL and how to handle them using IS NULL, IS NOT NULL, COUNT, COALESCE, and common data cleaning techniques. ## Lesson objectives In this lesson, we will learn how to work with values in SQL. In the previous lesson, we briefly saw and . But is an important SQL topic and should be explained separately. In real data, missing values are very common. For example: some employees may not have phone numbers some customers may not have email addresses some orders may not have payment dates yet some products may not have discount values some reports may have missing department or manager information These missing values are often stored as in SQL.