Learn how to check, replace, compare, and aggregate NULL values in a database query using common techniques and examples.

Learn how to optimize SQL queries for NULL values by following some best practices and techniques, such as using IS NULL or IS NOT NULL operators, avoiding NOT IN with NULL values, and more.

Apart from using COALESCE(), there are 2 other ways to replace NULL values in SQL Server. Let's understand this with an example. I have a Table tblEmployee, as shown in the diagram below. Some of the ...

1. **ISNULL(): **The ISNULL function have different uses in SQL Server and MySQL. In SQL Server, ISNULL() function is used to replace NULL values. 2. **IFNULL(): **This function is available in MySQL, ...