In the context of joins, what does null indicate in results?

In the context of joins, a null value in the results signifies non-matching values. When performing a join between datasets, the presence of null indicates that there was no corresponding record found in one of the datasets for a given key or join condition. For example, in an outer join, if a row from one dataset does not have a matching row in the other dataset, the columns that correspond to the non-matching dataset will be filled with null. This behavior is essential for identifying records that exist in one set but not in the other, thereby providing clarity on the relationship between the datasets being joined. Understanding this concept is crucial for effectively interpreting the results of your data analysis and making data-driven decisions.