What is a best practice for executing queries?

Performing filtering at the database level is considered a best practice for executing queries because it takes advantage of the database management system's optimization capabilities. When filtering is done at the database level, only the relevant data needed for the application is retrieved. This minimizes the amount of data transferred over the network and reduces the amount of memory consumed by the application, leading to better performance and faster response times.

Databases are designed to handle large volumes of data efficiently, using indexing and other optimization strategies to process queries quickly. By using these features, you ensure that the application runs efficiently and effectively uses resources.

Filtering in application memory can lead to unnecessary data being loaded, which may result in slower performance and increased resource consumption. Limiting the number of returned records is also beneficial but can be part of a broader strategy; it is most effective when combined with database-level filtering. Returning all records is generally not advisable, as it can overwhelm the application and lead to severe performance issues, particularly with large datasets. Hence, proper filtering at the database level is the optimal approach for efficient data retrieval.