How do nulls affect aggregate functions?

Null values can significantly impact aggregate functions in SQL and data analysis. Most aggregate functions, such as SUM, AVG, and COUNT, typically ignore nulls when calculating results, which can lead to unexpected outcomes. For instance, if a dataset has null values in a numeric column, the average calculated may not reflect the true average of all entries. To manage nulls effectively, it’s important to understand how they are treated by specific aggregate functions and consider using functions like COUNT(*) to include all rows, regardless of nulls.