To schedule a refresh of the data, you need to ensure that Tableau Server or Tableau Online can access the database without prompting for credentials. This can be done by embedding the credentials in the workbook or the published data source. You also need to extract the data from the database and publish it as a separate data source or as part of the workbook. A live connection would not allow you to refresh the data on a schedule, as it would always query the database directly. A hyper file is a format for storing extracted data, but it is not a requirement for scheduling a refresh. References:
* Tableau Certified Data Analyst Exam Prep Guide, page 10, section "Publishing and Scheduling Data Refreshes"
* Tableau Help: Embedding Database Credentials
* Tableau Help: Extract Your Data

To combine the tables by using Tableau Prep and include only values from Table1 that do not match any values in Table2, you should use a left only join. A left only join is a type of join that returns only the rows from the primary table (Table1) that have no matching rows in the secondary table (Table2). The field values from Table2 will appear as null values in the combined table. A left only join is also known as an anti-join or an exclusion join. References:
* Tableau Certified Data Analyst Exam Prep Guide, page 9, section "Preparing Data"
* Tableau Help: Join Your Data
* Tableau Help: Left Only Join

In Tableau, you can manage the visibility of different visualizations on a dashboard using various techniques.
Among the options provided, the most straightforward method to allow users to switch between two visualizations is to use show/hide buttons.
Here's why each option is or isn't suitable for the requirement:
A). A parameter and a calculated field: While it's possible to use a parameter and a calculated field to control which visualization is displayed, it requires creating a calculated field that responds to a parameter and then using that field to filter the view. This method can become complex and is not as user-friendly for simply showing and hiding visualizations.
B). Worksheet actions: Worksheet actions in Tableau typically allow users to interact with the data within a visualization, such as filtering data or highlighting related data points when clicking or hovering. They are not designed to control the visibility of entire visualizations on a dashboard.
C). Show/hide buttons: Show/hide buttons are a feature specifically designed to manage the visibility of dashboard elements. When you create a show/hide button, it can be configured to display or hide a particular visualization, container, or any other dashboard element when clicked. This provides a very intuitive interface for users to switch between visualizations.
D). Dashboard actions: Dashboard actions, like worksheet actions, are used to create interactions between sheets, such as filtering data or navigating to other sheets or URLs based on user interactions. They are not intended for toggling the visibility of visualizations.
Therefore, the correct answer is C. Show/hide buttons as they provide a user-friendly way to switch between visualizations on a dashboard without the need for complex calculations or actions that aren't meant for this purpose. The show/hide button feature is specifically designed for toggling visibility and offers a simple and effective solution for the requirement.

To create the Position column, you should use the FIRST () function. The FIRST () function returns the number of rows from the current row to the first row in the partition. For example, the first row in a partition will return 0, the second row will return -1, and so on. In this question, the partition is defined by the Segment field, and the table is sorted by the Sales field in descending order. Therefore, the Position column shows the offset of each row from the first row in each segment, based on the sales ranking. References:
* Tableau Certified Data Analyst Exam Prep Guide, page 11, section "Creating Calculated Fields"
* Tableau Help: FIRST Function