Tableau Interview Questions and Answers

Q2. What is Data Visualization?

Ans: A much advanced, direct, precise and ordered way of viewing large volumes of data is called data visualization. It is the visual representation of data in the form of graphs and charts, especially when you can’t define it textually. You can show trends, patters and correlations through various data visualization software and tools; Tableau is one such data visualization software used by businesses and corporates.

Q3. What are the differences between Tableau desktop and Tableau Server?

Ans: While Tableau desktop performs data visualization and workbook creation, Tableau server is used to distribute these interactive workbooks and/or reports to the right audience. Users can edit and update the workbooks and dashboards online or Server but cannot create new ones. However, there are limited editing options when compared to desktop.
Tableau Public is again a free tool consisting of Desktop and Server components accessible to anyone.

Q4. Define parameters in Tableau and their working.

Ans: Tableau parameters are dynamic variables/values that replace the constant values in data calculations and filters. For instance, you can create a calculated field value returning true when the score is greater than 80, and otherwise false. Using parameters, one can replace the constant value of 80 and control it dynamically in the formula.

Q5. Differentiate between parameters and filters in Tableau.

Ans: The difference actually lies in the application. Parameters allow users to insert their values, which can be integers, float, date, string that can be used in calculations. However, filters receive only values users choose to ‘filter by’ the list, which cannot be used to perform calculations.
Users can dynamically change measures and dimensions in parameter but filters do not approve of this feature.Most in-depth, industry-led curriculum in Tableau.

Q6. What are fact table and Dimension table in Tableau?

Facts are the numeric metrics or measurable quantities of the data, which can be analyzed by dimension table. Facts are stores in Fact table that contain foreign keys referring uniquely to the associated dimension tables. The fact table supports data storage at atomic level and thus, allows more number of records to be inserted at one time. For instance, a Sales Fact table can have product key, customer key, promotion key, items sold, referring to a specific event.

Dimensions are the descriptive attribute values for multiple dimensions of each attribute, defining multiple characteristics. A dimension table ,having reference of a product key form the fact table, can consist of product name, product type, size, color, description, etc.

Q7.What are Quick Filters in Tableau?

Ans: Global quick filters are a way to filter each worksheet on a dashboard until each of them contains a dimension. They are very useful for worksheets using the same data source, which sometimes proves to a disadvantage and generate slow results. Thus, parameters are more useful.

Q8. State limitations of parameters in Tableau.

Ans: Parameters facilitate only four ways to represent data on a dashboard (which are seven in quick filters). Further, parameters do not allow multiple selections in a filter.

Q9. What is aggregation and disaggregation of data in Tableau?

Ans: Aggregation and disaggregation in Tableau are the ways to develop a scatterplot to compare and measure data values. As the name suggests, aggregation is the calculated form of a set of values that return a single numeric value. For instance, a measure with values 1,3,5,7 returns 1. You can also set a default aggregation for any measure, which is not user-defined. Tableau supports various default aggregations for a measure like Sum, average, Median, Count and others.
Disaggregating data refers to viewing each data source row, while analyzing data both independently and dependently.

Q10. What is Data Blending?

Ans: Unlike Data Joining, Data Blending in tableau allows combining of data from different sources and platforms. For instance, you can blend data present in an Excel file with that of an Oracle DB to create a new dataset.

Q11. What is Content Filter?

Ans: The concept of context filter in Tableau makes the process of filtering smooth and straightforward. It establishes a filtering hierarchy where all other filters present refer to the context filter for their subsequent operations. The other filters now process data that has been passed through the context filter.
Creating one or more context filters improves performance as users do not have to create extra filters on large data source, reducing the query-execution time.
You can create by dragging a filed into ‘Filters’ tab and then, Right-Click that field and select ‘’Add to Context”

Q12. What are the limitations of context filters?

Ans: Tableau takes time to place a filter in context. When a filter is set as context one, the software creates a temporary table for that particular context filter. This table will reload each time and consists of all values that are not filtered by either Context or Custom SQL filter.Interested in a Tableau Career?

Q13. Name the file extensions in Tableau.

Ans: There are a number of file types and extensions in Tableau :

• Tableau Workbook (.twb).
• Tableau Packaged Workbook (.twbx).
• Tableau Datasource (.tds).
• Tableau Packaged Datasource (.tdsx).
• Tableau Data extract (.tde).
• Tableau Bookmark (.tdm).
• Tableau Map Source (.tms).
• Tableau Preferences (.tps)

Q14. Explain the difference between .twb and .twbx

Ans: .twb is the most common file extension used in Tableau, which presents an XML format file and comprises all the information present in each dashboard and sheet like what fields are used in the views, styles and formatting applied to a sheet and dashboard.But this workbook does not contain any data. The Packaged workbook merges the information in a Tableau workbook with the local data available (which is not on server). .twbx serves as a zip file, which will include custom images if any. Packaged Workbook allows users to share their workbook information with other Tableau Desktop users and let them open it in Tableau Reader.

Q15. What are Extracts and Schedules in Tableau server?

Ans: Data extracts are the first copies or subdivisions of the actual data from original data sources. The workbooks using data extracts instead of those using live DB connections are faster since the extracted data is imported in Tableau Engine.After this extraction of data, users can publish the workbook, which also publishes the extracts in Tableau Server. However, the workbook and extracts won’t refresh unless users apply a scheduled refresh on the extract. Scheduled Refreshes are the scheduling tasks set for data extract refresh so that they get refreshed automatically while publishing a workbook with data extract. This also removes the burden of republishing the workbook every time the concerned data gets updated.

Q16. Name the components of a Dashboard

Ans:

• Horizontal –Horizontal layout containers allow the designer to group worksheets and dashboard components left to right across your page and edit the height of all elements at once.
• Vertical –Vertical containers allow the user to group worksheets and dashboard components top to bottom down your page and edit the width of all elements at once.
• Text
• Image Extract : –A Tableau workbook is in XML format. In order to extracts images, Tableau applies some codes to extract an image which can be stored in XML.
• Web [URL ACTION] :-A URL action is a hyperlink that points to a Web page, file, or other web-based resource outside of Tableau. You can use URL actions to link to more information about your data that may be hosted outside of your data source. To make the link relevant to your data, you can substitute field values of a selection into the URL as parameters.

Q17. How to view underlying SQL Queries in Tableau? 

Ans: Viewing underlying SQL Queries in Tableau provides two options :

1. Create a Performance Recordingto record performance information about the main events you interact with workbook. Users can view the performance metrics in a workbook created by Tableau.
   Help> Settings and Performance> Start Performance Recording
   Help> Setting and Performance > Stop Performance Recording.
2. Reviewing the Tableau Desktop Logslocated at C:\Users\\My Documents\My Tableau Repository. For live connection to data source, you can check log.txt and tabprotosrv.txt files. For an extract, check tdeserver.txt file.

Q18. What is Page shelf?

Ans: Tableau provides a distinct and powerful tool to control the output display known as Page shelf. As the name suggests, the page shelf fragments the view into a series of pages, presenting a different view on each page, making it more user-friendly and minimizing scrolling to analyze and view data and information. You can flip through the pages using the specified controls and compare them at a common axle.

Q19. How to do Performance Testing in Tableau?

Ans: Performance testing is again an important part of implementing tableau. This can be done by loading Testing Tableau Server with TabJolt, which is a “Point and Run” load generator created to perform QA. While TabJolt is not supported by tableau directly, it has to be installed using other open source products.

Q20. Explain the concept of Dual Axis.

Ans: Dual Axis is an excellent phenomenon supported by Tableau that helps users view two scales of two measures in the same graph. Many websites like Indeed.com and other make use of dual axis to show the comparison between two measures and their growth rate in a septic set of years. Dual axes let you compare multiple measures at once, having two independent axes layered on top of one another.

Q21. How many maximum tables can you join in Tableau?

Ans: The maximum number of 32 tables can be joined in Tableau. A table size must also be limited to 255 columns (fields).

Q22. How to remove ‘All’ options from a Tableau auto-filter?

Ans: The auto-filter provides a feature of removing ‘All’ options by simply clicking the down arrow in the auto-filter heading. You can scroll down to ‘Customize’ in the dropdown and then uncheck the ‘Show “All” Value’ attribute. It can be activated by checking the field again.

Q23. How to add Custom Color to Tableau?

Ans: Adding a Custom Color refers to a power tool in Tableau. Restart you Tableau desktop once you save .tps file. From the Measures pane, drag the one you want to add color to Color. From the color legend menu arrow, select Edit Colors. When a dialog box opens, select the palette drop-down list and customize as per requirement.

Q24. What different products Tableau provide?

Ans:

• Tableau Server :on-premise or cloud-hosted software to access the workbooks built.
• Tableau desktop :desktop environment to create and publish standard and packaged workbooks.
• Tableau Public :workbooks available publicly online for users to download and access the included data.
• Tableau Reader :get a local access to open Tableau Packaged workbook

Q25. How can you display top five and last five sales in the same view?

Ans: Create two sets, one for top 5 another for bottom 5 and the join these two sets displaying a unique set of total 10 rows.

Q26. What is TDE file?

Ans: TDE is a Tableau desktop file that contains a .tde extension. It refers to the file that contains data extracted from external sources like MS Excel, MS Access or CSV file.
There are two aspects of TDE design that make them ideal for supporting analytics and data discovery.

• Firstly, TDE is a columnar store.
• The second is how they are structured which impacts how they are loaded into memory and used by Tableau. This is an important aspect of how TDEs are “architecture aware”. Architecture-awareness means that TDEs use all parts of your computer memory, from RAM to hard disk, and put each part to work what best fits its characteristics.

Q27. How to use group in calculated field?

Ans: By adding the same calculation to ‘Group By’ clause in SQL query or creating a Calculated Field in the Data Window and using that field whenever you want to group the fields.

• Using groups in a calculation.You cannot reference ad-hoc groups in a calculation.
• Blend data using groups created in the secondary data source:Only calculated groups can be used in data blending if the group was created in the secondary data source.
• Use a group in another workbook.You can easily replicate a group in another workbook by copy and pasting a calculation.

Q28. Can parameters have dropdown list?

Ans: Yes, parameters do have their independent dropdown lists enabling users to view the data entries available in the parameter during its creation.

Q29. What is the difference between joining and blending in Tableau?

• Joining term is used when you are combining data from the same source, for example, worksheet in an Excel file or tables in Oracle database
• While blending requires two completely defined data sources in your report.

Q30. What are Extracts and Schedules in Tableau server?

Ans: Data extracts are the first copies or subdivisions of the actual data from original data sources. The workbooks using data extracts instead of those using live DB connections are faster since the extracted data is imported in Tableau Engine.After this extraction of data, users can publish the workbook, which also publishes the extracts in Tableau Server. However, the workbook and extracts won’t refresh unless users apply a scheduled refresh on the extract. Scheduled Refreshes are the scheduling tasks set for data extract refresh so that they get refreshed automatically while publishing a workbook with data extract. This also removes the burden of republishing the workbook every time the concerned data gets updated.

Q31. How to view underlying SQL Queries in Tableau?

Ans: Viewing underlying SQL Queries in Tableau provides two options:

1. Create a Performance Recording to record performance information about the main events you interact with workbook. Users can view the performance metrics in a workbook created by Tableau.
   Help -> Settings and Performance -> Start Performance Recording
   Help -> Setting and Performance -> Stop Performance Recording.
2. Reviewing the Tableau Desktop Logs located at C:\Users\\My Documents\My Tableau Repository. For live connection to data source, you can check log.txt and tabprotosrv.txt files. For an extract, check tdeserver.txt file.

Q32. How to do Performance Testing in Tableau?

Ans: Performance testing is again an important part of implementing tableau. This can be done by loading Testing Tableau Server with TabJolt, which is a “Point and Run” load generator created to perform QA. While TabJolt is not supported by tableau directly, it has to be installed using other open source products.

Q33. Name the components of a Dashboard.

Ans:

• Horizontal – Horizontal layout containers allow the designer to group worksheets and dashboard components left to right across your page and edit the height of all elements at once.
• Vertical – Vertical containers allow the user to group worksheets and dashboard components top to bottom down your page and edit the width of all elements at once.
• Text – All textual fields.
• Image Extract  – A Tableau workbook is in XML format. In order to extracts images, Tableau applies some codes to extract an image which can be stored in XML.
• Web [URL ACTION] – A URL action is a hyperlink that points to a Web page, file, or other web-based resource outside of Tableau. You can use URL actions to link to more information about your data that may be hosted outside of your data source. To make the link relevant to your data, you can substitute field values of a selection into the URL as parameters.

Q34. How to remove ‘All’ options from a Tableau auto-filter?

Ans: The auto-filter provides a feature of removing ‘All’ options by simply clicking the down arrow in the auto-filter heading. You can scroll down to ‘Customize’ in the dropdown and then uncheck the ‘Show “All” Value’ attribute. It can be activated by checking the field again.

Q35 .How to add Custom Color to Tableau?

Ans: Adding a Custom Color refers to a power tool in Tableau. Restart you Tableau desktop once you save .tps file. From the Measures pane, drag the one you want to add color to Color. From the color legend menu arrow, select Edit Colors. When a dialog box opens, select the palette drop-down list and customize as per requirement.

Q36. What is TDE file?

Ans: TDE is a Tableau desktop file that contains a .tde extension. It refers to the file that contains data extracted from external sources like MS Excel, MS Access or CSV file.
There are two aspects of TDE design that make them ideal for supporting analytics and data discovery.

• Firstly, TDE is a columnar store.
• The second is how they are structured which impacts how they are loaded into memory and used by Tableau. This is an important aspect of how TDEs are “architecture aware”. Architecture-awareness means that TDEs use all parts of your computer memory, from RAM to hard disk, and put each part to work what best fits its characteristics.

Q37. Mention whether you can create relational joins in Tableau without creating a new table?

Ans: Yes, one can create relational joins in tableau without creating a new table.

Q38. How to automate reports?

Ans: You need to publish report to tableau server, while publishing you will find one option to schedule reports.You just need to select the time when you want to refresh data.

Q39. What is Assume referential integrity?

Ans: In some cases, you can improve query performance by selecting the option to Assume Referential Integrityfrom the Data menu. When you use this option, Tableau will include the joined table in the query only if it is specifically referenced by fields in the view.

Q40. Explain when would you use Joins vs. Blending in Tableau?

Ans: If data resides in a single source, it is always desirable to use Joins.  When your data is not in one place blending is the most viable way to create a left join like the connection between your primary and secondary data sources.

Q41. What is default Data Blending Join?

Ans: Data blending is the ability to bring data from multiple data sources into one Tableau view, without the need for any special coding. A default blend is equivalent to a left outer join. However, by switching which data source is primary, or by filtering nulls, it is possible to emulate left, right and inner joins.

Q42.What do you understand by blended axis?

Ans: In Tableau, measures can share a single axis so that all the marks are shown in a single pane. Instead of adding rows and columns to the view, when you blend measures there is a single row or column and all of the values for each measure is shown along one continuous axis. We can blend multiple measures by simply dragging one measure or axis and dropping it onto an existing axis.

Q43. What is story in Tableau?

Ans: A story is a sheet that contains a sequence of worksheets or dashboards that work together to convey information. You can create stories to show how facts are connected, provide context, demonstrate how decisions relate to outcomes, or simply make a compelling case. Each individual sheet in a story is called a story point.

Q44. What is the difference between discrete and continuous in Tableau?

Ans: There are two types of data roles in Tableau – discrete and continuous dimension.

1. Discrete data roles are values that are counted as distinct and separate and can only take individual values within a range. Examples: number of threads in a sheet, customer name or row ID or State. Discrete values are shown as blue pills on the shelves and blue icons in the data window.
2. Continuous data roles are used to measure continuous data and can take on any value within a finite or infinite interval. Examples: unit price, time and profit or order quantity. Continuous variables behave in a similar way in that they can take on any value. Continuous values are shown as green pills.

Q45. How to create stories in Tableau?

Ans: There are many ways to create story in Tableau. Each story point can be based on a different view or dashboard, or the entire story can be based on the same visualization, just seen at different stages, with different marks filtered and annotations added. You can use stories to make a business case or to simply narrate a sequence of events.

• Click the New Story tab.
• In the lower-left corner of the screen, choose a size for your story. Choose from one of the predefined sizes, or set a custom size, in pixels.

• By default, your story gets its title from its sheet name. To edit it, double-click the title. You can also change your title’s font, color, and alignment. Click Apply to view your changes.

• To start building your story, drag a sheet from the Story tab on the left and drop it into the center of the view

• Click Add a caption to summarize the story point.

• To highlight a key takeaway for your viewers, drag a text object over to the story worksheet and type your comment.

• To further highlight the main idea of this story point, you can change a filter or sort on a field in the view, then save your changes by clicking Update above the navigator box.

Q46. What is the DRIVE Program Methodology?

Ans: Tableau Drive is a methodology  for scaling out self-service analytics. Drive is based on best practices from successful enterprise deployments. The methodology relies on iterative, agile methods that are faster and more effective than traditional long-cycle deployment.

A cornerstone of this approach is a new model of partnership between business and IT.

Q47. How to use group in calculated field?

Ans: By adding the same calculation to ‘Group By’ clause in SQL query or creating a Calculated Field in the Data Window and using that field whenever you want to group the fields.

• Using groups in a calculation. You cannot reference ad-hoc groups in a calculation.
• Blend data using groups created in the secondary data source: Only calculated groups can be used in data blending if the group was created in the secondary data source.
• Use a group in another workbook. You can easily replicate a group in another workbook by copy and pasting a calculation.

Q48. Mention what is the difference between published data sources and embedded data sources in Tableau?

Ans: The difference between published data source and embedded data source is that,

• Published data source: It contains connection information that is independent of any workbook and can be used by multiple workbooks.
• Embedded data source: It contains connection information and is associated with a workbook.

Q49. Mention what are different Tableau files?

Ans: Different Tableau files include:

• Workbooks: Workbooks hold one or more worksheets and dashboards
• Bookmarks: It contains a single worksheet and its an easy way to quickly share your work
• Packaged Workbooks: It contains a workbook along with any supporting local file data and background images
• Data Extraction Files: Extract files are a local copy of a subset or entire data source
• Data Connection Files: It’s a small XML file with various connection information

Q50. How to embed views onto Webpages?

Ans: You can embed interactive Tableau views and dashboards into web pages, blogs, wiki pages, web applications, and intranet portals. Embedded views update as the underlying data changes, or as their workbooks are updated on Tableau Server. Embedded views follow the same licensing and permission restrictions used onTableau Server. That is, to see a Tableau view that’s embedded in a web page, the person accessing the view must also have an account on Tableau Server.

Alternatively, if your organization uses a core-based license on Tableau Server, a Guest account is available. This allows people in your organization to view and interact with Tableau views embedded in web pages without having to sign in to the server. Contact your server or site administrator to find out if the Guest user is enabled for the site you publish to.

You can do the following to embed views and adjust their default appearance:

• Get the embed code provided with a view: The Share button at the top of each view includes embed code that you can copy and paste into your webpage. (The Share button doesn’t appear in embedded views if you change the showShareOptions parameter to false in the code.)

• Customize the embed code: You can customize the embed code using parameters that control the toolbar, tabs, and more. For more information, see Parameters for Embed Code.

• Use the Tableau JavaScript API: Web developers can use Tableau JavaScript objects in web applications. To get access to the API, documentation, code examples, and the Tableau developer community, see the Tableau Developer Portal.

Q51. Design a view in a map such that if user selects any state, the cities under that state has to show profit and sales.

Ans: According to your question you must have state, city, profit and sales fields in your dataset.

Step 1: Double click on the state field

Step 2: Drag the city and drop it into Marks card.

Step 3: Drag the sales and drop it into size.

Step 4: Drag profit and drop it into color.

Step 5: Click on size legend and increase the size.

Step 6: Right click on state field and select show quick filter.

Step 7:  Select any state now and check the view.

Q52. Think that I am using Tableau Desktop & have a live connection to Cloudera Hadoop data. I need to press F5 to refresh the visualization. Is there anyway to automatically refresh visualization every ‘x’ seconds instead of pressing F5?

Ans: Here is an example of refreshing the dashboard for every  5 seconds.

All you need to do is replace the api src and server url with yours.

<!DOCTYPE html>

<html lang="en">

<head>

<title>Tableau JavaScript API </title>

<script type="text/javascript" src="http://servername/javascripts/api/tableau_v8.js"></script>

</head>

<div id="tableau Viz"></div>

<script type='text/javascript'>

var placeholderDiv = document.getElementById("tableau Viz");

var url = "http://servername/t/311/views/Mayorscreenv5/Mayorscreenv2";

var options={

hideTabs:True,

width:"100%",

height:"1000px"

};

var viz= new tableauSoftware.Viz(placeholderDiv,url,options);

setInterval (function() {viz.refreshDataAsync()},5000);

</script>

</body>

</html>

Q53. Suppose my license expires today, will users be able to view dashboards or workbooks which I published in the server earlier?

Ans: If your server license expires today, your username on the server will have the role ‘unlicensed’ which means you cannot access but others can. The site admin can change the ownership to another person so that the extracts do not fail.

Q54. Is Tableau software good for strategic acquisition?

Ans: Yes! For sure. It gives you data insight to the extent that other tools can’t. Moreover, it also helps you to plan and point the anomalies and improvise your process for betterment of your company.

Q55. Can we place an excel file in a shared location and and use it to develop a report and refresh it in regular intervals?

Ans: Yes, we can do it. But for better performance we should use Extract.

Q56. Can Tableau be installed on MacOS?

Ans: Yes, Tableau Desktop can be installed on both on Mac and Windows Operating System.

Q57. What is the maximum no. of rows Tableau can utilize at one time?

Ans: Tableau is not restricted by the no. of rows in the table. Customers use Tableau to access petabytes of data because it only retrieves the rows and columns needed to answer your questions.

Q58.What are sets?

Ans: Sets are custom fields that define a subset of data based on some conditions. A set can be based on a computed condition, for example, a set may contain customers with sales over a certain threshold. Computed sets update as your data changes. Alternatively, a set can be based on specific data point in your view.

Q59. What are groups?

Ans: A group is a combination of dimension members that make higher level categories. For example, if you are working with a view that shows average test scores by major, you may want to group certain majors together to create major categories.

Q60. What is a hierarchical field?

Ans: A hierarchical field in tableau is used for drilling down data. It means viewing your data in a more granular level.

Q61. What is Tableau Data Server?

Ans: Tableau server acts a middle man between Tableau users and the data. Tableau Data Server allows you to upload and share data extracts, preserve database connections, as well as reuse calculations and field metadata. This means any changes you make to the data-set, calculated fields, parameters, aliases, or definitions, can be saved and shared with others, allowing for a secure, centrally managed and standardized dataset. Additionally, you can leverage your server’s resources to run queries on extracts without having to first transfer them to your local machine.