Interview Questions


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Tableau Interview Questions

Posted in Interview Questions
Tableau Interview Questions

Tableau Interview Questions & Answers

 

Tableau is one of the commonly used business intelligence tools out there. This tool helps analyze data without being overwhelmed by the software elements. 

 

Being such an important tool, there is a great demand for Tableau experts. 

 

If you want to prepare for interviews, we have mentioned some of the most important and frequently asked questions that will help you to understand the basics of Tableau. You will not require prior Tableau knowledge to understand this article, as we have covered the basics till the advanced part. 

 

Let’s get started with Tableau and be ready to rock the interview.

 

1. What is Tableau?

Tableau is a business intelligence software capable of handling massive data and enables interactive visualization of the data gathered from various sources. 

 

what is tableauImage Credits: Tableau

 

It helps many businesses work on numbers to get insights for growth and development. This tool allows people to connect to the respective data. 

 

Some of the competitors available in the market for Tableau are Apache Superset, Qlik, and Metabase.

 

2. What are the advantages of Tableau?

Below are the advantages of using Tableau for your business:

 

  • It shows high performance as it can handle millions of data rows without any complexity. One of the major advantages of using Tableau is that you will get different types of visualization.

     

  • It enhances mobility for the users on the go, as this tool is available for mobile users like iOS and Android users and allows them to keep track of the statistics. You can use all features on mobile that are available for the desktop version.

     

  • Tableau has a strong, expanded, and active community of enthusiastic people willing to help you with your issues related to Tableau. You can easily get various resources and guides online for your reference. 

     

  • Tableau is used by users looking to actively deploy the mobile BI.

     

  • Tableau comes with easy and frequent updates featuring several elements to make the tool useful for its users in various ways.

     

  • You will find this tool a low-cost solution when compared to its alternatives in the market, such as Qlik.

     

  • It has a simple user interface that is easy to learn, understand, and work with.

 

3. What are the challenges while using Tableau?

Below are some challenges while using Tableau:

 

  • With Tableau, you will not get the automatic refreshing of the reports. You will not get an option of scheduling; thus, this requires manual effort to update the back-end data.

     

  • This tool does not provide the developers the freedom to import customized visuals.

     

  • Tableau has conditional formatting, so if you have to make the configuration similar to multiple columns, the user needs to do it manually as there is no direct way for doing this. This is a very time-consuming activity. 

     

  • Tableau has a static parameter that can be used only to select a single value. So if there is a change in the data, you need to update the parameter manually every time. You will not get any automatic way of doing that.

     

  • The layout of Tableau’s dashboard will be distorted if you are trying to view the dashboard in a resolution that is different from the developer’s screen resolution. 

     

  • With this tool, you can only do the basic preprocessing and changing the data type. Ideally, the data will get exported to the perfect tables, thus requiring data cleansing, which requires additional tools for preprocessing the data before loading. 

 

4. What are some features of Tableau?

Below are the features of Tableau.:

 

  • Dashboard: Provides you a complete view of your data using visual objects, stories, allows you to add multiple objects, provides different types of layouts and formats, and allows users to apply the right filters. It allows you the option to copy the dashboard or its elements from one workbook to another. 

     

  • Collaboration and sharing: You will get many options for collaborating with other users and sharing critical data in the form of visualization, dashboards, etc. You can share the data securely to get quick feedback.

     

  • Live and in-memory data: You can connect to live data sources and in-memory data, allowing the users to get the data from various sources without any limitations. It offers you additional features for data connectivity such as automatic extract refreshes, etc.

     

  • Robust security: Tableau has a full-proof security system that ensures secure authentication and permission systems for establishing data connections. Also, Tableau can be easily integrated with other security protocols like Kerberos.

     

  • Mobile view: You will get a mobile version for Tableau allowing the users to create their dashboards and reports on the go. You will be able to create customized mobile layouts.

 

5. What are some uses of Tableau?

  • Business Intelligence
  • Data Visualization
  • Data Blending
  • Data Collaboration
  • It will help translate the query into visualization
  • It will help create no-code data queries
  • Helps in the analysis of the real-time data
  • For managing extensive metadata
  • For importing large size of data

 

6. Explain data visualization in Tableau.

Data visualization is specified as the pictorial representation of the data or the gathered information using maps, charts, graphs, and other visual elements. With the help of the visual representation of data, you will understand the complex trends. Various companies take the help of this method to get better insights into their data and create a better user experience by easily providing complex data.

 

7. What are the various products of Tableau?

There are five different products of Tableau:

 

  • Tableau Server
  • Tableau Desktop
  • Tableau Reader
  • Tableau Online
  • Tableau Public

 

8. What is Tableau Desktop?

This is one of the products of Tableau, allowing a user to code and then alter the reports accordingly. The process will start with creating the reports and charts that will create a dashboard, and the entire work is done within the Tableau Desktop. 

 

Tableau Desktop is further classified as follows depending on the connectivity and the data sources:

 

  • Tableau Desktop Personal

This version is close enough to the Tableau Desktop version. But in the personal desktop version, the workbook is a private mode with limited access. It means that you cannot post the workbook and can use it for personal use.

 

  • Tableau Desktop Professional

This version is very similar to the Tableau Desktop, where the work created within the Tableau Desktop will be published on the Tableau Server. This version will have full access to all data types, making it suitable for publishing work on the Tableau Server.

 

9. What is Tableau Reader?

This tool helps the user get the visualizations and workbooks generated using Tableau Public or Tableau Desktop. You can filter this data but with limited modifications. As any user with the workbook can view it with the help of the Tableau reader, this is not secured.

 

10. What is Tableau Server?

This product is used to share the visualizations and the workbook created using the Tableau Desktop application. After uploading the work on the server, it will be accessible to everyone. For sharing the dashboard in Tableau Server, you need to publish that work in Tableau Desktop. However, the licensed users don’t need to install Tableau Server as they only have to log in to verify the reports. 

 

11. What is Tableau Public?

This product is suitable for users who focus on saving money. As the name suggests, the generated workbooks are not saved locally but are being uploaded to Tableau’s public cloud so that the work will be accessible to the general public. It is a cost-effective version which makes it more suitable for users who want to learn and share data with other people.

 

12. What is Tableau Online?

Tableau Online is a sharing tool that is similar to Tableau Server. But in the case of Tableau Online, data will be saved on cloud servers maintained by the Tableau group. There is no storage limit on the data that you can publish on Tableau Online. Both Tableau Server and Online will require the workbook generated using Tableau Desktop for broadcasting the data. 

 

13. What is the difference between Tableau and MS Excel?

Both Tableau and Excel are data analysis tools having different approaches for exploring data. Excel works with the columns and rows within the spreadsheets, while Tableau works with the data with the help of drag and drop features. 

 

Tableau

MS Excel

A data visualization tool providing the pictorial and graphical representations of gathered data.

A spreadsheet tool where the data is presented in rows and columns. 

It will provide insights that you never thought possible. You can get various types of interactive visualizations, deploy data drilling tools, and explore several datasets without any specific knowledge of the insights you are looking for.

For using Excel, you should have prior knowledge of the insights that you want and then work with various formulae. 

It is an easy and interactive approach.

You should have programming knowledge for getting real-time data visualization.

 

14. What are the different types of Tableau files?

 

  • Workbooks: It may contain one or more worksheets and dashboards.
  • Bookmarks: It will store a single spreadsheet and allow you to share the work easily.
  • Packaged workbooks: It has a workbook that supports the background images and data of the local file.
  • Data extraction files: These are the local copy of the entire data source.
  • Data connection files: It is an XML file that will contain the required information related to the connection.

 

15. Explain the importance of data servers in Tableau.

You can use the data servers for two purposes:

 

  • It will sync all the data continuously from the datasets to past calculations. It will create the aliases to definitions that can be accessed from anywhere. 
  • With the data servers in place, you do not have to download all the data to the local machine for running a visualization report. You can easily use the data off the internet via servers.

 

16. Explain measures and dimensions in Tableau.

Both measures and dimensions are the attributes that help in defining the specific dataset within Tableau. 

 

Measures are defined as the measurable quantities that are being analyzed against dimensions. You can add any number of measures to a single string that is being checked by dimensions. For example, for checking the number of students within a school, the name, address, and roll number are considered the measures. 

 

But, dimensions are the descriptions that enable the visualization to happen. It allows the user to describe the metrics uniquely. 

 

17. Explain filters and different types of filters in Tableau.

With a filter, you can restrict the unwanted data and help in displaying the data we want to see. There are three different types of filters available:

 

  • Quick Filter: You can use this filter for viewing the filtering options and filter the worksheets available on the dashboard while you change the values dynamically during the run time.
  • Context Filter: You can use this filter for filtering the data that will be transferred to the various worksheets. Whenever a worksheet runs a query on the data source, a temporary flat table will be created to compute the chart. This table will contain all the values that are not filtered out by any context filter.
  • Datasource Filter: This filter is adept at restricting the data from the database; depending on the dimension you select. Alternatively, you can create a traditional filter by dragging a file onto it.  

 

18. Explain discrete and continuous in Tableau.

A discrete dimension is one where you treat each entry differently from other entities. For example, product names and countries are an example of discrete dimensions.

A continuous dimension is considered to be a part of another series. For example, dates and years.

 

19. Explain groups in Tableau.

The group is considered to be the collection of the categories that will create a single overarching subcategory. 

 

20. Explain sets in Tableau.

A set is similar to the groups but with the output instead of the input. A collection of the output values that are associated with a specific category is considered as a set. 

For example, in the superstore dataset, if you plot the profit in all the categories, you will be able to create the set of profits for any category.

 

21. Explain parameters in Tableau.

A parameter is considered the dynamic value that will save time by avoiding the need to change the filter frequently. You can easily create a parameter for the constant values within your filters, reference lines, and required calculations. You can make the changes in the parameter values from the dashboard.

 

22. What is a heat map?

A heat map is a qualitative method for visualizing and comparing data. The heat map will allow you to compare the quantum method of the measures for several categories within a table without the need to create a graph. 

Generally, higher values are represented in the darker shapes of red while the lower values are represented by shades of blue. However, you can change the colors as per your ease and understanding.

23. What is a treemap in Tableau?

With the help of a treemap, you will be able to analyze the data quantitatively based on the size of the pictorial representation. The rectangle is the basic unit of the treemap that will represent the sum of all the values of the chosen measures. Then the created rectangle will be further divided into smaller rectangles depending on the measures in each category of the chosen dimension.

24. Explain the data engine in Tableau.

The data engine of Tableau is an analytical database that is specifically designed for achieving the instant query response, predicting performance, integrating seamlessly into the existing data infrastructure. If you are working with a large amount of data, it might take some time to import, create indexes, and sort the data, but everything else will work seamlessly. The data engine is not an in-memory technology as the imported data will be stored in a disk.

 

25. Explain the dual-axis in Tableau.

It is a phenomenon that is being used by the users for viewing two scales of two measures in the same graph. Various websites use dual-axis for comparing two measures and their growth rate in a specific set of years. With the help of the dual-axis, you can easily compare multiple measures at a single time that can have two independent axes layered on top of one another. Below is an example.

 

26. Explain aggregation and disaggregation in Tableau.

Aggregation is the process of viewing the values or measures at the higher and more summarized levels. Whenever you use the measure on the shelf, Tableau will aggregate the data via summing all the data. If aggregation is being applied to any field, you can determine it easily as the function will be visible in front of the field name. For example, the field “sum” will be displayed as the sum(sales). 

On disaggregating the data, you will get each row of the data source. This is useful while analyzing the measures that can be used within the view. For example, let’s say you’re analyzing the result of a survey with the age of the users at one axis. You can aggregate the Age field to determine the average age of participants or disaggregate the data to determine what age participants are.

 

27. How do you check the underlying SQL queries in Tableau?

We have two options for viewing the underlying SQL queries in Tableau.

 

  • First, record the performance information regarding the main events. You can check the performance metrics in a Tableau workbook.
  • For checking the metrics, go to:
    Help -> Settings and Performance -> Start Performance Recording
    Help -> Setting and Performance -> Stop Performance Recording.
  • You can check the Tableau repository folder under the My Documents folder on your system. If you want to check for the live connection, check the log.txt and the tabprotosrv.txt files. If you want to check for the extract, check the tdeserver.txt file.

 

28. What is a TDE file?

TDE stands for Tableau Desktop — it’s a file that has a .tde extension. This file stores the data extracted from external sources such as MS Excel, MS Access, and others. Below we have mentioned some aspects of the TDE file that makes it more suitable for supporting analytics and data discovery:

 

  • TDE is a store that stores the data in columns.
  • Another important aspect is that TDEs are architecture aware which means that TDEs will use all the parts of your computer memory from RAM to hard disk and utilize every part while working.

 

29. What is a story in Tableau?

A story is a sheet that will hold a sequence of the worksheets or the dashboards that work together for conveying any useful information. 

In Tableau, you are allowed to create a story showing the connection between the facts, provide a meaningful context, and specify how the decisions are related to the outcomes. 

Each sheet that is present within the story is known as a story point.

 

30. What are the steps for creating a story?

You can create a single story in various ways. Each story point can be based on any view or dashboard. The entire story can be based on the same virtualization, annotations, etc. Then, you can use a story to create a business case for demonstrating a sequence of events.

 

  • First, click on the New Story tab.
  • Then choose a size for your story from the lower-left corner. Select any of the predefined sizes, or set a custom size as per your requirement, in pixels.
  • By default, the story will take its title from the sheet name. For changing the title name, double-click the title. Select your choice of title’s font, color, and alignment and click Apply for implementing the changes.
  • Now, drag a sheet from the Story tab that is available on the left and drop it into the center of the view.
  • Then, click Add option for adding a caption for summarizing the story point.
  • You can use comments for highlighting a key takeaway for your viewers by dragging a text object over to the story worksheet.
  • Then, you can apply a filter or sort on a field in the view, then save the changes by clicking the Update option.

 

31. Explain the difference between .twbx and .twb.

The difference is as below:

 

  • .twbx

The .twbx stores all of the important information that is required for building the visualization along with the data source. This is known as a packaged workbook that will compress the package of files altogether.

 

  • .twb

The .twb stores the instructions such as how to interact with the data source. During visualization creation, Tableau looks at the data source for building the visualization with an extract. You can’t share it alone as it contains only instructions, and the data source needs to be attached separately.

 

32. Explain the Level of Detail (LOD) expression in Tableau.

You can use the LOD expression for running the complex queries that include more than a single dimension at the data source level rather than bringing all the data to the Tableau interface. 

Consider the following example:

We have shown the scales for the Furniture category and its sub-categories. Now looking at the sales for the furniture as a whole, rather than focusing on its sub-categories, you need to remove the sub-category from the calculation field as shown below.

LOD expression in Tableau

Now, the visualization looks as shown below.

33. How can you schedule a workbook in Tableau after publishing it?

Below are the simple steps for scheduling the workbook in Tableau after you are done publishing it.

 

  • First, log in to your Tableau server, then navigate to the content -> data sources or content -> workbooks (it depends on what type of content you want to refresh).
  • Now select the checkbox for the data source or workbook that you are looking to refresh and then select the actions -> extract refresh.
  • You will get a dialog box, select the schedule and then select the appropriate schedule. If the selected schedule is available, then specify the type of refresh you want — either full or incremental refresh.

 

34. How can you embed a webpage in a dashboard?

To embed the web page in the dashboard, you can simply follow the below-mentioned steps:

 

  • First, navigate to the dashboard.
  • Look for the ‘Web Page’ option available under ‘Objects’ and double click it.
  • Then you need to provide the URL (here we used https://en.wikipedia.org/wiki/) of the webpage in the dialog box.
  • You can see the webpage will appear on the dashboard.

 

35. How do you make the webpage dynamic?

To make the website dynamic, you can follow the below-mentioned simple steps:

 

  • First, we will start by bringing Map by Sales into view, displaying the state's name and its sales.
  • Then, navigate to the dashboard.
  • Look for the ‘Web Page’ option available under ‘Objects’ and double click it
  • You will get a dialog box. You do not have to provide the URL there and click on Ok. 
  • Select the Dashboard from the menu and select the ‘Action’ option.
  • Then click on the ‘Add Action’ option and then select ‘Go to URL.’
  • Now, you have to provide the URL, ‘https://en.wikipedia.org/wiki/’ under the URL option. Click on the arrow available next to it and then select the ‘State.’
  • Then click on the ‘Select option’ and click ‘Ok.’
  • Now, whatever state you select, you will get the Wikipedia page for that particular state.

 

36.  How do you optimize the performance of a Tableau dashboard?

There are various ways for optimizing the performance of the Tableau dashboard:

 

  • You can use the fields and records that are important and remove the fields that are not required from the visualization or use the correct extract filters.
  • Make sure you use the limited filters by using actions and parameter filters. This will help in reducing the query loads.
  • Use the min/max rather than the average, as average functions will require more processing time than the min/max functions.
  • Make sure to use the boolean or numerical calculations rather than the string calculations, as string processing will take more time.

 

37. How can we perform data blending?

There are two ways in which you can perform data blending:

 

  • One is the automatic way where Tableau will automatically define the relationship between the two data sources depending on some common dimensions and matching values. This type of relationship is indicated in orange.
  • Another way is a manual way where the user will define the relationship manually.

 

38. Mention functionalities of data blending.

Below are some functionalities of data blending.

 

  • There is a specific relationship between the primary and secondary data sources.
  • Whenever you perform the data blending, each worksheet has a primary connection and can have several secondary connections.
  • The blue color is for the primary connections, and all secondary connections will be in orange color. 

 

39. What is the blended axis?

With a blended axis, you can show the multiple measures within a single axis, and all the marks are specified in a single pane.

 

  • With the blended axis, you will be able to drag a dimension in a column
  • You can drag the first measure in the column
  • You can drag the second measure in the existing axis
  • Us/multiplemeasures_blendedaxes.html

 

40. What is data modeling?

Data modeling is the analysis of data objects mainly used to identify the relationships among the data objects. It is not only a seamless process for creating diagrams for software, but is also a technologically advanced way to produce object-oriented programming.  

 

How data modeling works is pretty straightforward: A data model connects tables across databases, then issues a set of instructions. This way, every time you use the data in Tableau, it will recall the data model, whether you configure it automatically or manually.

 

Remarkably, data modeling utilizes conventional schemas and techniques. In turn, they offer an easy way of defining and handling data resources across a variety of platforms. Before this cutting-edge way of modeling data was adopted, you had to jump through many hoops.  For instance, you had to create a data model by first outlining all the tables and then match them simultaneously — a process that was often time-consuming and costly. 

 

With data modeling, you can do the following with ease:

  • You can do Tableau augments, fix joins and unions by simply specifying relationships between them. 
  • You can create easy-to-understand SQL queries based on specific fields. 
  • You are guaranteed speed on your workbooks. How? Data modeling will allow you specific visualizations by shortening SQL queries.
  • You use it to reduce duplication of records. Thanks to its ability to define data sources at the visualization level, data modeling alleviates a need for multiple LOD calculations.
  • You won’t experience any data blending issues. It allows you to navigate any situation that was previously required by blending. 

 

41. What is KPI in Tableau?

With Tableau, you can quickly and effectively analyze the effectiveness of any company depending on the key indicators with the help of the key performance indicators in the shape cards. 

 

First, you need to create a calculated field and then specify the values as success or failure depending on the required parameters. Then you will be plotting a chart using the dimension and the created calculated field and change to shapes automatically. Then specify the success and failure values to KPI in shape cards for better understanding.

 

42. Explain a bin in Tableau.

In Tableau, bins are the containers of equal size used to store the data values that can be easily fit in the bin size. 

 

In simpler words, the bins will help in grouping the data into groups of equal size that helps in viewing the data systematically.  You can consider all the discrete fields as a set of fields.

 

43. Explain analysis in Tableau.

To analyze the data plotted on the chart, you can use the inbuilt features of Tableau. You can use various tools such as adding an average line to the chart that Tableau will calculate after dropping the tool on the chart. You can use additional features such as clustering, percentages, etc., for exploring and inspecting data. You can use all these tools from the analyze tab on each sheet for creating any chart. These features will only be visible if you can implement them to a specific worksheet.

 

44. What is the page shelf in Tableau?

With the help of the page shelf, you can easily understand multiple charts more efficiently. If you have multiple plots within a single sheet and want to view those plots one by one, you can drag and drop the dimension responsible for creating charts rather than a single chart to the page shelf. After that, you will get various options to scroll through different charts one by one and you can analyze them. 

 

45. What is a Tableau developer?

A Tableau developer is a person who understands and knows the process of creating data visualizations and useful insights using the raw data from various sources. The person should also be responsible for creating advanced dashboards that are being used by other people and make it easier for people to work with Tableau efficiently.

 

46. How can you hide the dashboard in Tableau?

You cannot hide a dashboard in Tableau, but if you are publishing the dashboard to a website, you will be able to hide the dashboard. For this, you need to set a command for showing the dashboard only when you click a specific button. But rather than hiding the dashboard, you can go for hiding the sheets before you publish the dashboard. Then by default, the people will be able to see only the dashboard but not the individual sheets.

 

47. How can you create a hierarchy in Tableau?

By default, some hierarchy has been created of the data sources depending on the field values. You can even create your customized hierarchy by dragging the field on the top of another in the data pane. Then you can enter the name of the hierarchy and then press Ok. You can also add some additional fields to your hierarchy. Having data being arranged in the hierarchy will make it easier to scroll through the categories of data.

 

48. How do you connect MongoDB with Tableau?

Below are the steps for connecting MongoDB with Tableau:

 

  • For connecting your MongoDB with Tableau, you will require an additional driver. You need to download and install that driver from here
  • After installing, you need to open Tableau and select the MongoDB BI connector in front of the connect section.
  • If you cannot find it in the main list, then under the “To a server” menu, you will see an option named “More.” There you can find the MongoDB BI Connector. 
  • Now, you need to enter the name of the server, enter the username and password for the specific database. Then, select the “Require SSL” checkbox while you connect to an SSL server. 
  • Then select “Sign in” to go with the data source.

 

49. Explain the cascading filter in Tableau.

Cascading filters can be considered as the preference given to a specific filter that then applies additional filters on top of the previously filtered data sources. You can right-click on the filter that you want to use as the main filter. But you have to make sure that it is set as all values in the dashboard and then select the subsequent filter. You need to select the relevant values for cascading the filters. This will help improve the dashboard's performance as the cascading filters will take less time than running all the filters on the source data.

 

50. How can you improve performance in Tableau?

You can improve the performance of Tableau in various ways, but the most common method is to use the extract option on the data sources, which is considered to be the most powerful tool. After you are done with the creation of the dashboard, then you can run the performance recorder. You will get the sheets displaying the performance of Tableau. 

 

  • You can also improve the performance by reducing the number of masks on your view.
  • Make sure to use fewer filters.
  • Also, make sure to use include instead of exclude fields. 
  • If you want to filter a large chunk of data, then you should use the context filter.
  • For reducing the query execution time, you can use the cascading filters.

 

51. What is the minimum version of Android OS required to run Tableau mobile?

Tableau mobile can be run on Android devices with version 7 or higher. Tableau mobile can be used to view the visualizations created on Tableau Desktop, Tableau Server, and Tableau Online.

 

52. What is a scatter plot in Tableau?

You can use the scatter plot to visualize two or more measures with or without the dimensions. For plotting a scatter plot, you must have one measure in a row and one in the column. Then you can do further detailing using several dimensions of cards. With the help of the scatter plot, you can plot the data points in an empty place that will take some shape depending on the values present within measures.

 

53.  How do you show the axis in Tableau?

In Tableau, you can show and hide any axis depending on your requirement. For this, you need to right-click the axis and then select the “deselect” option to hide the axis. If you want to show the axis, then again right-click the fields in the row or column and select the “show header” option to get back the hidden axis.

 

54. How do you add a logo to the Tableau dashboard?

You can add a logo in your Tableau dashboard by going into the objects pane and selecting the import image option. Make sure to change the default tiled option to the floating type.

Then you can drag and drop the object to the dashboard and choose the desired logo from your system. The image should be in a format like .jpg or .png. If you want to use it as a background, you can use the small drop-down option on the right side of the image. After that, you need to select the send-to-back option to increase the image's size to use it as a watermark logo.

Conclusion 

In this modern time where data is considered to be the most crucial thing in the IT industry, it is equally important to get an understandable view of that data. Tableau is the way to create a visualization of the data from various sources — thus making it a hot skill of today’s world.

 

Here is the list of the most frequently asked questions in a Tableau interview. This article will help you to understand the basics of Tableau along with some advanced features. Whether you have some prior knowledge of Tableau or not, this guide is good enough to brush up on your skills at the last moment of the interview.

 

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