Tableau is a Business Intelligence and Business Analytics platform that is used for using data to make forecasts, analyze trends, and sift through chaotic data sets to find patterns and logical conclusions. Tableau was founded by Chris Stolte, Pat Hanrahan, and Christian Chabot in the year 2003 due to a computer Science project undertaken at Stanford University. In the year 2019, Salesforce acquired Tableau with its mission intact which is to make it easy for people to handle data even if they don’t possess a certain degree of expertise. Tableau can be used for Data Visualization, Data Blending, Data Collaboration, Real-time data analysis, and importing and managing large datasets.
It facilitates the exploration and management of data along with the sharing of data and key insights across devices and platforms. The products of Tableau are user-friendly are helpful to one and all right from experts like analysts, and data scientists to laymen like students, teachers, and business users. Tableau prides itself on the flexibility, security, and variety that it provides. Tableau helps organizations to be more data-focused and use data to draw their inferences and business insights which will help them make decisions with mathematical precision.
Tableau was started in 2003 and since then it has come a long way and includes significant milestones in its journey and is still innovating. It began with Stolte’s Code productization in Version one and version two introduced Quick Table Calc, Quick filter, and Extracts. Tableau Public was launched in the fifth version in the year between 2008 to 2010 while Tableau Online was added through version 8 launched circa 2013. Since then, it has made multiple innovations like Blending, Data Engine, Prep Builder, Tableau Catalog, and Einstein in Tableau until it was acquired by Salesforce in 2019. In the year 2024, Tableau Pulse has been launched and it will be generally available in the same year as its beta testing operations were concluded last year.
Now that we have discussed the history of Tableau Public, let’s dive into some of the most commonly asked questions in Tableau interviews.
Top 50 Tableau Interview Questions
Ques 1. What is Tableau Reader?
Ans. Tableau Reader is a desktop application used to open and work with data visualizations that were created in Tableau Desktop. Through Tableau Reader, these packaged workbooks with extracted data sources can also be shared locally. So, Tableau Reader is there to interact and share the data, but you cannot edit formulas or charts which can be done via Tableau Desktop.
Ques2. What is Tableau Online?
Ans. Tableau Online is a platform on the web and it is used for data analytics and visualization along with the ability to interact with dashboards and share reports and online collaboration with colleagues. Its main advantage is accessibility as it can be accessed via a web browser or a mobile application, basically from any device and from anywhere.
Ques 3. What are the components of Tableau Server architecture?
Ans. The Tableau Server has the following components in its architecture:
- Application Server to process the hold browsing and permissions for Tableau Server interface.
- VizQL Server to send queries directly to the data source and be presented with a resultant image
- Data Server allows you to control and store Tableau Data sources
- Backgrounder to refresh scheduled extracts and manage other background tasks
- Gateway/Load Balancer trails requests to other components
Ques 4. What is the main advantage of Tableau?
Ans. There are multiple advantages associated with Tableau such as it can handle millions of data rows and it doesn’t require any coding knowledge or technical inclination to be able to use it.
Ques 5. What are the default properties in Tableau?
Ans. The default properties menu in Tableau contains default settings for multiple functions that can be performed within Tableau. It consists of default settings for aggregation, comments, number formatting, color, shape, and totals (based on the type of field).
Ques 6. What is an Extract connection?
Ans. Connections in Tableau are used to source data for performing operations and creating visualizations. An Extract connection works on a batch of data which will need to be refreshed periodically to get updated data and the changes won’t reflect in the report unless data is refreshed.
Ques 7. What are the differences between Live and Extract connection?
Ans. An Extract connection works over batches of data that need to be refreshed from time to time for updated data reflected in the report. Live connections let you have real-time data which means that any changes made to the data source will immediately be reflected in the report. So, an Extract connection is a bit more time-consuming than a Live connection.
Ques 8. What is the best Data format for Tableau?
Ans. The Data format that is best to be used in Tableau Desktop is probably the tables formatted like a spreadsheet. So, the data is divided or stored in rows and columns, no matter how many, is the best data format for Tableau.
Ques 9. Explain the process of data connections.
Ans. The following steps have to be followed for data connections in Tableau:
- To connect to Tableau Server, Go to Connect Pane and search for Data, select Tableau Server, enter the name of the server, and select Connect. To connect to Tableau Cloud, select Tableau Cloud under Quick Connect.
- Sign into Tableau Server by entering username and password or Tableau Cloud by entering email and password.
- Select data to connect from the Search for dialog, it has a scrollable list.
Ques 10. What are the various components of Tableau Workspace?
Ans. The Tableau Workspace contains components like a toolbar, menu, data window, legends, and sheets along with cards that hold shelves. It also contains a view which is a canvas to do the data visualization and a Side Bar which contains a Data Pane and Analytics pane. It has a status bar to display information about the current view and Sheet tabs.
Ques 11. What is Dual Axis?
Ans. Dual Axis Map in Tableau is a map that contains two sets of geographic data within one map visualization overlaid on top of one another. Dual Axis Chart is a way to visualize data that combines two different chart types in a single graph where they share the X-axis but have differing Y-axes to present two data sets simultaneously.
Ques 12. What is a Blended Axis?
Ans. A blended axis is a blend of different measures on a single axis, It is deployed when there is a need to show two measures on the same axis and is used in multi-line graphs or charts with more than two measures to depict. In order to create a blended axis, you have to take the axis that you want to add, drag, and drop it over the pre-existing axis.
Ques 13. How to synchronize a Dual Axis?
Ans. Synchronizing axes would mean getting the different axes in a data visualization unit to use the same scale. In order to synchronize a dual axis, you have to right-click (control-click on Mac) the Secondary axis and then select the Synchronize axis.
Ques 14. What is the difference between Reports and Views?
Ans. Reports in Tableau is the presentation of information plain and simple while Views refers to creating a dashboard for data visualization which gives context and visual appeal to the data. It is the graphical representation of the same data that is there in Reports which is a deep dive into a single data point and doesn’t accommodate variety.
Ques 15. How the Extract file is created and what is its format?
Ans. The steps to create an Extract file are as follows:
- Click on the Data Source tab
- Change the connection type from Live to Extract
- Click Create Extract and you will see the Creating Extract dialog box where you can track the progress of your extract file, or you can just click on Notify Me when complete and it will let you know.
The Tableau Data Extract files have an extension of .tde
Ques 16. How do you convert measure to dimension?
Ans. To convert a measure to dimension in the Data pane, you can do one of the following:
- Click and drag the field from the measures area in the Data pane to the dimensions area; or
- Right-click (control-click on Mac) the measure that you want to convert in the Data pane and click on convert to dimension.
Ques 17. How many types of filters are there in Tableau?
Ans. Tableau has six types of filters and all of them are listed below:
- Extract Filter to separate extracted data from data source
- Data Source Filter to sift through data in data source proportion
- Context Filter to apply a relevant and actionable context to the visualization
- Dimension Filter is used in qualitative fields
- Measure Filter includes operations like sum, mean, standard deviation, etc.
- Table Calculation Filter is used to look into data without filtering hidden data.
Ques 18. Why do we use actions?
Ans. Tableau actions are used to show additional details in the same visualization without adding another graphic which would clutter the dashboard. It makes the data visualization look more dynamic and succinct.
Ques 19. Does the highlight function work on the Dashboard?
Ans. Yes, the Highlight function works on the Tableau Dashboard and highlighters added to worksheets also appear in Dashboards and Stories.
Ques 20. What is a Context filter?
Ans. A context filter is an independent filter which is subject to all other filters that are applied to that particular data point. It can be used to force a specific filter to be carried out first or to create dependent numerals involving the data of interest.
Ques 21. What is a Normal filter?
Ans. In Tableau, filters are used to restrict data sets and a Normal filter is the one that is used to do the same thing but on a selected dimension or measure. It can be created by dragging a field onto a shelf of filters.
Ques 22. What is the difference between a Normal Filter and a Context filter?
Ans. Normal filters restrict the database based on a selected dimension or a measure while Context filter is used to restrict data that is being transferred to each individual worksheet.
Ques 23. What are Quick filters and why are they used?
Ans. The quickly available filters in Tableau that can be accessed using a right click on dimension or measure are called Quick filters. They are dynamic filters and are used to view filter options and filter individual worksheets in the dashboard itself while changing the values.
Ques 24. How can we assign filter data to all or selected sheets?
Ans. To apply filter to worksheets, you just have to navigate to the filters shelf, right-click the field Select Apply to all worksheets and then select one of the following according to your needs:
- All using related data sources
- All using this data source
- Selected Worksheets
- Only this Worksheet
Ques 25. Which filter is better with respect to performance?
Ans. Data Source filters are the best when judged with respect to performance in Tableau. It can be used to restrict the data set that is visible or available to the users when you publish your workbook.
Ques 26. What is conditional formatting in Tableau?
Ans. Conditional formatting is a procedure available in Tableau that can be used for creating rules or formulas that are based on the data values. It also makes identification of particulars easier leading to highlighting certain values.
Ques 27. How many charts are there in Tableau? Name a few.
Ans. Tableau’s show me feature contains a total of 24 charts and some of them are as follows:
- Bar, Line, and Pie Charts which are the ones used in mathematical data interpretation
- Map Chart which is used to show geographical data points
- Box and Whisker Plot is used to show the distribution of a data set
- Heat Map which is used to do color-coded comparisons
Ques 28. What is Cross Tab in Tableau?
Ans. A Cross tab in Tableau is also known as a Text Table because it shows data in a textual and tabular form. It is created by adding one dimension on the rows shelf and another dimension on the columns shelf.
Ques 29. What is a Combinational Chart and when is it used?
Ans. A Combinational Chart is a chart type that is used for combining views so as to save space on the Dashboard. A combo chart can be created by sharing either the X or Y axis and then it can have two of the remaining axes. It can be used to convey distinctions or make a comparison between conflicting data points.
Ques 30. When do we use Line Charts and when are Bar Charts used?
Ans. The Line Chart can be used to show the continuous evolution of one data set such as data trends whereas the Bar Chart can be used to compare data, highlight differences, and reveal highs and lows, etc.
Ques 31. What chart is used to show the actual and target data?
Ans. A bullet graph chart is used to show the actual and target data as they are used to compare forecasts to actual numbers that you have in your data set.
Ques 32. What is the Gantt Chart?
Ans. Gantt Chart in Tableau is there to showcase interdependencies between various factors in the data visualization, it creates an illusion of workflow. To create a Gantt Chart, you must select/connect your data where it needs both a measure and a dimension.
Ques 33. What are Treemaps and how are they helpful?
Ans. A tree map in Tableau is the presentation of data in nested rectangles, they can showcase their context by using rectangles of various shapes and sizes or by color coding them. They are helpful in visualizing a large number of categories that are interconnected with each other.
Ques 34. What is Data Blending?
Ans. Data Blending in Tableau refers to the process of combining data from multiple sources to create a Dashboard. It is used to take data from secondary sources and combine it with the primary source bringing in additional information to the whole visualization.
Ques 35. What are the data types supported in Tableau?
Ans. Tableau supports seven data types, and they are listed below:
- String Values
- Data Values
- Date & Time Values
- Numeric Values
- Boolean Values
- Geographical Values
- Cluster or Mixed Values
Ques 36. What is the difference between joining and blending?
Ans. Within Tableau, joining and blending both perform the task of data combination but joining means data source combination at the lowest granularity before aggregation while blending combines data sources after aggregation has been done on individual data sources separately.
Ques 37. What do you mean by ‘discrete’ and ‘continuous’ in Tableau?
Ans. Discrete and Continuous govern the data representation in Tableau where ‘Continuous’ means an uninterrupted whole and ‘Discrete’ means a separate and distinct individual.
Ques 38. What is the difference between Sets and Groups in Tableau?
Ans. The major point of difference is that Sets are dynamic while the Groups are not. With Sets, you are presented with choices like in/Out or Show members in a set whereas Groups only come with an option of group/ungroup. So, you can either be a part of a group or not but with Sets the categorization becomes more layered.
Ques 39. What is a parameter in Tableau?
Ans. Parameters in Tableau are workbook variables that are used to replace the constant value in a calculation, filter, and reference line. It includes elements like numbers, date, and calculated fields, etc.
Ques 40. What are Heat maps?
Ans. Heat maps are a type of chart among many available in Tableau, it is a color-coded chart that can be used to establish or showcase patterns, trends, and relationships among the data.
Ques 41. How many maximum tables can be joined in Tableau?
Ans. The maximum number of tables that can joined in Tableau is 32 Tables. The table size is also limited as it can only have a maximum column count of 255 columns (fields).
Ques 42. What is a Hierarchical Field?
Ans. A Hierarchical Field in Tableau is an arrangement of data where the particulars are presented at various levels, it is used to show entities that are at varying levels of hierarchy or related to each other in terms of upper and lower. You can create hierarchies by dragging a dimension as a level under the principal dimension.
Ques 43. What are the different products of Tableau?
Ans. Tableau has multiple different products catering to the various needs of its users:
- Tableau Desktop
- Tableau Prep
- Tableau Mobile
- Tableau Online
- Tableau Public
- Tableau Cloud
and many more.
Ques 44. What is the difference between aggregated and non-aggregated data in Tableau?
Ans. Aggregations are computed at the level of detail in the view which will return one value for several records. On the other hand, non-aggregated data are computed at the level of every record in underlying data which will return one value for one record.
Ques 45. How is Tableau better than traditional BI tools?
Ans. Tableau offers several advantages over traditional BI tools such as handling bulky data quickly and has a myriad of options for data visualization.
Ques 46. What is the difference between the .twb and .twbx extensions?
Ans. The .twb is an extension for an XML document that shows all selections and layouts made by you in the Tableau Workbook. The .twbx extension is a zipped archive file that contains the .twb extension file along with external files like background images.
Ques 47. What are to be considered for a good Dashboard?
Ans. To create a good dashboard, the following considerations have to be kept in mind:
- Involve businesspeople in Dashboard Design
- Use an iterative dashboard design approach
- Allow drill-down capabilities within Dashboards
- Include actionable information
- Choose between percentage and real numeric values
- Show relevant filters
- Follow consistent and differential color coding
- Test the dashboard on different screens
Ques 48. What is Story in Tableau?
Ans. Tableau Story is a feature that is used to show key insights that serve as solutions to data questions through the use of logically connected visuals. It is built by using a collection of sheets in the Workbook known as Story points.
Ques 49. What are the platforms Tableau server can run on?
Ans. Tableau Server supports Linux and Windows Operating Systems. Tableau products can run on platforms like Citrix environments, Microsoft Hyper-V, Parallels, VMware (including vMotion), Amazon Web Services, Google Cloud Platform Microsoft Azure, etc.
Ques 50. How do you publish Tableau Reports to the Tableau Server?
Ans. The steps to publish a Tableau Workbook are as follows:
- When the concerned workbook is open in Tableau Desktop, Click on the Share option in the Toolbar
- In the Publish Workbook dialog select the project that is going to be published
- Name the Workbook
- Under Data Sources, Select Edit and for authentication, select Allow Refresh access or Embed Password.
- Click Publish
Conclusion
In conclusion, Tableau’s ability to handle large datasets and its user-friendly interface has made it a top choice for businesses and individuals alike. With its innovative features and services, Tableau can help you make sense of complex data sets and create stunning visualizations that can improve your presentations.
I hope this Q&A article will be a valuable resource for you as you prepare for your Tableau interview. By studying these commonly asked questions and their answers, you can increase your chances of landing your dream job and securing a competitive salary package. Good luck!