What feature allows users to create database queries visually in OutSystems?

The feature that allows users to create database queries visually in OutSystems is Aggregates. Aggregates provide a user-friendly interface that simplifies the process of retrieving and manipulating data without the need for hand-written SQL. This visual approach is particularly beneficial for developers, as it encapsulates the complexities of database interactions, enabling them to focus on building applications rather than dealing with intricate SQL syntax.

By using Aggregates, developers can drag and drop entities, set filters, specify sorting, and define relationships, all within an intuitive environment. As users construct the query, they can see a visual representation of the data being queried, which helps in understanding how different entities relate to one another.

In contrast, the other options mentioned are not designed for visual query creation within the OutSystems platform. Excel is primarily a spreadsheet application, SQL refers to the structured query language used for database management, and Visual Basic is a programming language that does not pertain to the visual querying features in OutSystems. Thus, Aggregates stands out as the correct answer for querying databases visually within the OutSystems environment.