Description: Null handling in SQL refers to the techniques used to manage null values in SQL queries and operations. A null value represents the absence of data and can arise in various situations, such as when a field has not been filled out or when a data point is not applicable. Proper management of these values is crucial to ensure data integrity and the accuracy of query results. In SQL, null values can affect the behavior of comparison and aggregation operations, which can lead to unexpected results if not handled properly. For example, when performing a query that includes a WHERE clause, a null value is not considered equal to another null value, which may result in certain records being excluded from the results. To address this challenge, specific functions and operators are used, such as IS NULL, IS NOT NULL, COALESCE, and NULLIF, which allow developers and data analysts to effectively manage and manipulate these values. Optimizing SQL queries that involve nulls not only improves the accuracy of results but can also influence the overall performance of the database, as well-structured queries are more efficient and faster.
