Data has become the new currency of trade and every organization big or small wishes to have a bite of it. In these fast-paced times and the ever-expanding domain of the data industry, predicting trends by analyzing data has become of the utmost importance. The analysis of huge data sets using Data visualization tools has become all the more imperative and the need of the hour, with a shortage in the demand for professionals who are skilled in this art of data analytics and their demand on a constant rise over the last few years.

Data Visualization has started a new trend in the data industry with the demand for skilled individuals soaring sky high. It allows the professional to make a smarter decision-making process with the least granular data that they can get or scrub all the ‘Noisy Data’ to gain meaningful insights into the business. Companies are ready to compensate any professional who can analyze the company’s data and put it on the path of growth and success. This blog will extremely be helpful to anyone who has completed a certified course in Tableau and wishes to start looking for a good-paying job that uses Tableau as it is core competence software. Make certain to go through the most frequently asked tableau interview questions:-

Q1. What is Tableau?

• Is a business intelligence Software
• Helps in creating a link between datasets
• Aids in visualization and creating interactive dashboards

Q2. What are the different sub-products of Tableau?

The different sub-products of Tableau are:-

Tableau Desktop – This is a premium version of the Tableau software. There are 2 plans for the software. The first one is for $ 999 for personal use for a year. The second option is $ 9,999 for professional use for a year. In both versions, the user using the Tableau desktop can create visualizations, all listed data sources can be connected using the app, access can be restricted to certain individuals, and many other features.

Tableau Online – Helps the user publish dashboards/reports in real-time with colleagues for easier and faster business intelligence solutions, with complete access to colleagues to leave ideas on the dashboard with their color tag without changing the original data.

Tableau Public – This product of Tableau allows the user to create visualizations but does not allow the document to be saved anywhere except the Tableau server where once the workbook is posted it is available for the public viewing purpose.

Tableau Reader – It is a free desktop application that allows the user to view visualizations and dashboards, without the access to edit or interact with the visualization created.

Tableau Server – This is enterprise-level software that allows the user to upload or save a visualization or dashboard in the cloud server allocated for the company.

Q3. What are the different data types in Tableau?

Tableau supports the following data types:-

1. Boolean – TRUE / FALSE
2. Date – Date values ( December 14, 2020)
3. Date & time – Date & Timestamp values ( December 14, 2020, 18:12 PM)
4. Geographical values – geographical mapping (New York, France, India, Singapore)
5. Text / String – Text or string values (Welcome to Tableau)
6. Number (Decimal) – Decimal numbers (5.0000)
7. Number (Whole) – Whole numbers (6)

Q4. What are Measures and Dimensions?

Measures are numeric metrics or quantifiable quantities of data, which are evaluated by dimension tables. Numbers are stored in a table that keys referring uniquely to the associated dimension tables. The table supports data storage at molecular levels and thus allows multiple records to be inserted at the same time. E.g., the Sales table can have a product key, customer ID key, several units sold key etc.

Dimensions are definitive attribute values for multiple dimensions of each attribute, defining multiple characteristics. A dimension table can have the reference of the key product from the table which may consist of the product name, size, color, type etc.

Q5. Difference between .twb & .twbx extensions?

• .twb is a .xml document that includes all the selections & data that the user may have used in a Tableau workbook, it does not include any data.
• .twbx is a ‘zipped’ file consisting of a .twb and any other file that may have been used by the user like extracts, background images etc.

Q6. What are the varieties of joins used in Tableau?

They are a lot similar to the joins one finds in SQL, it is a joining method for combining data on a common key

Inner join – the resulting table consists of values that have matches in both the tables

Left join – The table consists of all values from the left table and corresponding matches from the right table.

Right join – It is the other way around to the left join with the corresponding matches from the left table.

Outer join – The table consists of all values from both the tables

Union Join – This is another style of merging two or more tables by attaching rows of data from one table to another.

Q7. Describe the distinction between Joining & blending?

Merging data from two or more different sources is data blending. E.g., data from multiple sources i.e., MS Excel, SQL Server, Oracle etc are pooled into one Tableau workbook. In data blending, each data source consists of its own set of dimensions & measures.

Joining is when two or more tables from the same data source are amalgamated into one workbook. The combined tables or sheets consist of a common set of dimensions and measures.

Q8. Is there a difference between groups and sets in Tableau?

A Tableau group is a one-dimensional representation of data, used to create a higher-level category by using lower-level category members. Tableau sets can have several conditions and may be grouped across multiple dimensions/measures.

The key disparity here is that all the groups will comprise of the same customers even if their profits change later on. In the case of sets, if the profit changes then the top five and bottom five customers will change accordingly.

Did you Know?

We cannot use groups in calculated fields, but we can use sets.

Q9. In Tableau what is a ‘Parameter’?

A parameter is a dynamic value that a user may choose, and also use to replace constant values in calculations, filters, and reference lines.

Q10. Difference between Heat maps & TreeMaps?

Heat Maps are used to compare categories using color and size. Using this method, the user may distinguish between two measures.

Tree Maps are used to represent hierarchical data. The space in this view is divided into rectangles that are sized and ordered by a measure.

Q11. What is Tableau worksheet, dashboard, story & workbook?

• Much like MS Excel, Tableau uses a workbook and sheet file structure.
• A workbook consisting of sheets may be referred to as a worksheet, dashboard or a story.
• A worksheet includes a single view along with shelves, legends and data pane.
• A dashboard is an assortment of views from numerous worksheets.
• A story is a categorization of worksheets or dashboards that work together to communicate information.

Q12. What do you understand by blended axis?

A blended axis is used for merging two measures that share the same axis when they have the same scale.

Q13. What is the use of a Dual-axis?

This feature allows the user to compare measures which are useful when the user wishes to compare two measures that have different scales.

Q14. What is the difference between a Blended axis and a dual-axis?

The difference between a blended axis and a dual-axis chart is that the blended axis uses the same scale, while a dual-axis can have two different scales or two marks cards.

Q15. What is the rank function in Tableau?

Based on a measure, ranking is assigning a position within a category.

Q16. How can one schedule a Workbook in Tableau, post its publication?

After signing into the Tableau server:-

• go to Content > data sources or Content > Workbooks, depending on the type of content the user wishes to refresh.
• Choose the checkbox for the data source or workbook The Operator intends to refresh, and then pick Actions > Extract Refresh
• In the Refresh Extracts dialog, opt for Schedule a Refresh and complete the subsequent moves:
  1. Pick the schedule The Operator wishes for.
  2. If offered, specify whether The Operator would like a complete or incremental refresh.

Q17. How to deal with Null and other special values?

If the field comprises of vacant values or if there are zeros or negative values on a logarithmic axis, Tableau would not be able to plot them. Tableau flashes an indicator in the lower right corner of the view, which once the user clicks are displayed the following options to choose from:

• Filter Data
  Omits all the null values from the visualization using a filter. In that case, the unimportant values are also omitted from any further calculations used in the visualization.
• Show Data at Default Position
  Displays the data at a default location on the axis.

Q18. How to embed a webpage in a Dashboard?

By following these steps any user can embed a webpage in a dashboard

• Go to dashboard
• Double click on the ‘Webpage’ alternative available in the ‘Objects’ option 
• Enter the URL of the webpage in the dialog box that appears

Q19. How to display the webpage as an infographic?

Start by bringing up the map into view, which will showcase the states name

• Go to the dashboard.
• Double click the ‘Webpage’ option available under ‘Objects.’ 
• Do not feed in a URL in the dialog box that appears and click on Ok. 
• Click on the Dashboard in the menu and choose ‘Action.’
• Click on ‘Add Action’ and pick ‘Go to URL.’
• Enter the URL in the option provided. Click on the arrow next to it and pick out ‘State.’
• Click on ‘Select option’ and hit ‘Ok.’

Now, when The Operator clicks on any state, it will bring up the webpage of that state and this is how a dashboard is made dynamic.

Q20. How to optimize the performance of a dashboard?

There are many ways to enhance the performance of a dashboard:

• By maximizing the number of fields and records. The user can exclude unused fields from the visualization or use extract filters.
• By restricting the number of filters used, by preventing quick filters and applying action & parameter filters instead. These filters are accountable for diminishing query loads. 
• Use Min/Max instead of using the Average function because average functions require more processing time than Min/Max.
• The use of Boolean or numerical calculations aids the computers, as they can process integers and Boolean much more rapidly than strings.

Q21. What visualization solutions would be used in the given scenario’s?

• To show the average of sales totals across a range of product categories and sub-categories – TreeMap
• To demonstrate the period of events or activities – Gantt Chart
• To display quarter wise growth – Waterfall Chart

Q22. How many tables can The Operator join in Tableau?

A maximum of 32 tables can be merged in Tableau.

Q23. What are the different connections a user can make with their dataset?

The user can either connect live to their data set or extract data onto Tableau.

• Live: Connecting live to a data set directly impacts the software’s computational processing and storage functions. Fresh queries will go to the database and will be reflected as new or updated within the data.
• Extract: An extract will make a dummy file of the data to be used by Tableau’s data engine. The dummy file of the data can be refreshed on a recurring schedule as a whole or incrementally attached data. One way is to set up these schedules is via the Tableau server.

The advantage of using Tableau extract over a live connection is that extract may be used anywhere without any connection and The Operator can build their visualization without connecting to the database and impacting the functionality of the system.

Q24. What are Shelves in Tableau?

They are designated areas in Tableau software, where the user may place the fields or the data with which The Operator chooses to create a visual.

Q25. What is the Tableau Data server?

Tableau server functions as the mediator between Tableau users and data. Tableau Data Server permits the operator to upload and communicate data extracts, sustain database links, as well as recycle calculations and field data. This means that any changes that the user makes to the dataset, calculated fields, parameters, aliases or definitions can be saved and shared with others. Permitting a centrally secured, managed, and standardized dataset. Additionally, the user may choose to pull up from the server’s resources to run queries on extracts without having to transfer them to the system in use.

Q26. Define the Tableau data engine?

Tableau Data Engine is a spectacular feature in Tableau. It is an investigative database designed to achieve instant query response, predictive performance, integrate seamlessly into existing data infrastructure with zero limitations to loadable data. If the user works with a large amount of data, it does not take time to import or create indexes and sort out data and after that speeds up the process. Tableau Data Engine is not in-memory technology. Post analysis the data is stored in a disk after being imported and the RAM is liberated for further tasks.

Q27. What are the different types of Filters in Tableau and how are they different from each other?

Filters in Tableau are used to restrict data from the database.

The different types of filters are:-

1. Normal Filter:-It is used to restrict data based on selected dimension or measure from the database. A traditional filter can be created by just dragging the field onto the ‘Filters’ shelf.
2. Quick Filter:- This filter helps view the filter or the filtering options used in each worksheet on a dashboard whilst changing a few values dynamically during runtime.

• Context filter:– This is used to filter the data that is transferred to each worksheet. When a worksheet queries a data source it generates a provisional table which it utilizes to compute the chart. These provisional tables comprise of all the values that are not sorted out by either the Custom SQL or the Context Filter.

Q28. What is Aggregation & Disaggregation of data?

The process of viewing numeric values or measures at higher and more concise levels of the data is called Aggregation. When the Operator places a measure on a shelf, Tableau automatically accumulates the data, usually by summing it. The Operator can easily determine the aggregation applied to a field because the function always appears in front of the field’s name on being placed on a shelf. For example, Sales becomes SUM(Sales).  The Operator can aggregate actions using Tableau only for relational data sources. Multidimensional data sources contain aggregated data only. In Tableau, multidimensional data sources are supported only in Windows operating systems.

Disaggregating the data allows the user to view every row of the data source which can be useful when The Operator is evaluating countermeasures that The Operator may want to use both independently and dependently in the view. E.g., The Operator may be evaluating the results from a product gratification survey with the age of applicants along one axis. The Operator can aggregate the Age field to determine the average age of participants or break down the data to determine what age participants were most satisfied with which of the products.

Q29. What are Extracts & Schedules in a Tableau Server?

Data extracts are the primary copies of the original data from the data sources. The workbooks which use data extracts instead of using live database connections are quicker as the extracted data is imported to the Tableau Engine. After mining of data, the operator can publish the workbook which also publishes the extracts in Tableau Server. Nevertheless, the workbook and extracts will not refresh until the operator applies a scheduled refresh on the extracted data. Planned Refreshes are the programed tasks put in place for data extraction refreshers so that the data is refreshed automatically while publishing a workbook with extracts. This also removes the trouble of republishing the workbook every time the concerned data gets updated.

Q30. How to view underlying SQL Queries in Tableau?

To view SQL queries, Tableau provides two options:-

1. Create a performance recording
2. Review the Tableau desktop logs

Q31. How to do performance testing in Tableau?

Performance testing is an integral part of imparting Tableau in the user’s work culture. This can be done by load testing the Tableau server with ‘TabJolt’.

Q32. Name the components of a Dashboard?

• Horizontal –Horizontal component allows the user to group worksheets and dashboard components left to right across the page and makes changes to the right of all elements simultaneously.
• Vertical –Vertical containers allow the operator to club worksheets and dashboard elements from top to bottom whilst editing the width of all elements at once.
• Text – All text related fields.
• Image Extract  –A Tableau workbook is in an XML format. To extract pictures, Tableau applies certain codes to mine an image that can be stored in XML format.
• Web –A URL measure is a hyperlink that directs the user to a Web page, file or other web-based resources outside of Tableau. The Operator can use URL actions to link to more information about the data that may be hosted outside of The Operator data source. To make the link relevant to The Operator data, The Operator can substitute field values of a selection into the URL as parameters.

Q33. From a Tableau auto-filter, how can one eradicate ‘All’ options?

The auto-filter provides an option for removing ‘All’ options by simply selecting the down arrow in the auto-filter heading. The Operator can also scroll down to the ‘Customize’ section in the dropdown and then uncheck the ‘Show All’ value attribute. It can be activated by checking back the field again.

Q34. How to add custom color to Tableau?

Adding a custom color refers to the use of a power tool in Tableau. On saving the .tps file restart The Operator Tableau desktop. From the measures, the pane drags the desired color onto the ‘Colour’ pane. From the color legend menu arrow, select ‘Edit Colours’. Once the dialog box opens, select the color The Operator wishes to customize The Operator Tableau in.

Q35. What is a TDE file?

A .tde file is an extension file that consists of data being extrapolated from external sources like MS Excel, MS Access etc. There are two features of the TDE fabrication which makes them perfect for data discovery & analytics. The features are:-

1. It is a columnar storage structure
2. The structure is solely responsible for the way they are loaded in Tableau. ‘TDE’s are architecturally aware and make the best use of each component of the computer hardware ranging from the RAM to the hard disk to perfectly fit it’s computing needs.

Q36. How to automate reports in Tableau?

To automate reports in tableau, the user would need to: –

1. Publish a report to the Tableau server
2. Whilst doing so the user will find an option for schedule reports
3. The operator needs to Select the frequency in how many minutes or hours he/she wishes to refresh the data.

Q37. Describe Assume Referential Integrity?

In certain scenarios, query performance may be improved by choosing the ‘Assume referential integrity’ option from the Data menu. On using this option, Tableau would compile the joined table in the query only if special referencing is made by the fields in the visualization.

Q38. What is a default Data Blending Join?

Data blending join allows the user to extract and compile data without the use of any special coding from several data sources into one Tableau Visual. A default data blend join functions as a left outer join but by switching the primary data source or by perforating the nulls it becomes possible to mimic left-right and inner joins.

Q39. In Tableau what does the term ‘Story’ imply?

The term ‘Story’ implies a sheet that consists of a sequence of worksheets or dashboards that work in tandem to convey a message. The user may create stories to show links between facts, provide context, showcase decision-making outcomes or simply make a compelling argument. Every single sheet in a story is known as a story point.

Q40. Describe the distinction between ‘Discrete’ and ‘Continuous’ in Tableau?

‘Discrete’ & ‘Continuous’ dimensions are the two types of data roles present in Tableau: –

• ‘Discrete’ data roles are distinct and separate values and can only take up individual values in a range. These values are shown as blue-colored pills on the shelves and blue colored icons on the visualization window.
• ‘Continuous’ data roles are continuous data measures and can take on any value within an infinite or finite interval. Continuous variables behave similarly and are shown as green pills in the sheet.

Q41. How can you create stories in Tableau?

There are several ways of creating stories in Tableau. Every story point can either be viewed on the same visualization or can be based on a distinct dashboard or visualization which can be seen at different stages with various annotations and marks filtered added to them. You can use stories to make a business argument or narrate an order of events. To create a story in Tableau the user may follow the following steps:-

1. Click on the ‘New Story’ tab
2. From the lower left-hand corner choose from a set of pre-defined or custom sizes for your story in pixels.
3. By default, you would notice your story taking the name of the sheet attached to it.
4. To edit the title, double click the title and make changes to the font, color and alignment of the text and then click on ‘Apply’ to view the changes made.
5. To start building your story, drag the sheet from the story tab on the left and drop it in the center of the visualization
6. Click on ‘Add a Caption’ to review the story point
7. To focus on the key idea of the story for the viewers, the user may either drag a text object to the story worksheet and type in a comment or change a filter and then save the changes by clicking on the ‘Update’ button above the navigator box.

Q42. Describe the DRIVE program methodology?

Also, referred to a Tableau Drive, it is a methodology for clambering out self-service analytics. Tableau Drive is based on some of the best practices and successful enterprise deployments. The process relies on a much precise, iterative and responsive technique which is swift and efficient than the old school long cycle implementations.

Q43. Describe the distinction between embedded data sources and Tableau published data sources?

• Published data source

It consists of connection information that is independent of any workbook and may be used in multiple workbooks.

• Embedded data source

It consists of connection information related to the workbook.

Q44. Mention the different Tableau files?

There are primarily 5 types of Tableau files: –

1. Workbooks – Hold one or more worksheets or dashboards.
2. Bookmarks – Consists of a single worksheet and makes it is easy to share the sheet.
3. Packaged Workbooks – It holds a workbook and any supporting data or images related to the workbook.
4. Data Extraction Files – These files are a copy of the subset of the entire data source.
5. Data Connection Files – It is a minute .xml file with multiple connection info.

Q45. How to insert views on a Webpage?

As an operator Tableau allows you to insert infographics in blogs, webpages, web applications, wiki pages, and intranet portals. Inserted visualizations refresh and get updated as the foundation data changes, or the workbook is updated on the Tableau server.

As the user following steps may be followed to insert visuals and to adjust their appearance:-

Get the embedded code provided with a visual: The Share button at the top of each visual comprises of an embed code that the user can copy and paste into the webpage. (The Share button does not appear in embedded views if you switch the ‘Show Share Options’ parameter to false in the coding)

Customize the embedded code: The operator may choose to customize the inserted code using factors that control the toolbar, tabs, and more.

Use the Tableau JavaScript API: Web developers often use Tableau JavaScript API in web applications. To gain access to the API, documentation, code examples, and the Tableau developer community. Check out the Tableau Developer Portal.

Q46. Fabricate a visual in a map so that if a user were to select any state, the cities under the state should show profit and sales?

As per the requirement, the data set should consist of fields about state, city, profit and sales fields. The next step is:-

• Double click on the state field
• Tug on the city and drop it into the Marks card
• Tug on the sales and drop it into size
• Tug on the profit and drop it onto the color
• Click the size legend to expand the size
• Right-click on the state field and opt for show quick filter
• Choose any state and view the visual.

Q47. Does Tableau work for a strategic acquisition?

Certainly, Tableau provides the user with data understandings to an extent other tools might not be able to. Also, it helps the user to strategize and point out inconsistencies and innovate the process for the benefit of the firm.

Q48. Can a user place an Excel file in a shared location and use it to generate a report and refresh it on regular intervals?

Yes, the user is allowed to do so using Tableau. But for higher performance using Extract is highly recommended.

Q49. Is Tableau available for macOS?

Tableau Desktop is obtainable for both Windows and Mac operating systems.