Tableau is one of the most popularly used BI tools across the globe. In this Tableau Interview Questions blog, you will be able to brush up on your Tableau skills and crack the job interview in your dream company. So, before going for any job interview in Tableau, go through this well-researched set of generally asked questions in Tableau interviews:
Q1. Compare QlikView with Tableau.
Q2. How is the Context Filter different from other Filters?
Q3. What is the disadvantage of Context Filters?
Q4. What are the five main products offered by Tableau?
Q5. What is the latest version of Tableau Desktop?
Q6. What is data visualization?
Q7. Why Tableau?
Q8. What are Filters? How many types of Filters are there in Tableau?
Q9. What is aggregation and disaggregation of data?
Q10. How to remove the Show All option from a Tableau Auto Filter?
Here are the three parts into which the Tableau interview questions are categorized:
Watch this Tableau Interview Questions & Answers:
Basic Interview Questions
1. Compare QlikView with Tableau.
|Working with multidimensional data
|Support for PowerPoint
||Limited by RAM
2. How is the Context Filter different from other Filters?
- Whenever we create a Context Filter, Tableau will create a temporary table for this particular Filter set and other Filters will be applied on the Context Filter data like cascade parameters.
- Suppose, we have created a Context Filter on countries, USA and India, Tableau will create a temporary table for these two countries’ data and if we have any other Filters other will be applied on these two countries’ data if we don’t have any Context Filter, each record will check for all Filters.
3. What is the disadvantage of Context Filters?
- The Context Filter is not frequently changed by the user—if the Filter is changed, the database must be recomputed and the temporary table has to be rewritten, slowing performance.
- When we set a dimension to context, Tableau creates a temporary table that will require a reload each time the view is initiated. For Excel, Access, and text data sources, the temporary table created is in an Access table format. For SQL Server, MySQL, and Oracle data sources, we must have permission to create a temporary table on our server. For a multidimensional data source, or cubes, temporary tables are not created, and Context Filters defined which Filters are independent and which are dependent.
4. What are the five main products offered by Tableau?
Tableau offers five main products:
- Tableau Desktop
- Tableau Server
- Tableau Online
- Tableau Reader
- Tableau Public
5. What is the latest version of Tableau Desktop?
Tableau Desktop 2019.4 (as of November 6, 2019)
6. What is data visualization?
Data visualization refers to the techniques used to communicate data or information by encoding it as visual objects (e.g., points, lines, or bars) contained in graphics.
7. Why Tableau?
Whether our data is in an on-premise database, a database, a data warehouse, a cloud application, or in an Excel file, we can analyze it with Tableau. We can create views of our data and share it with colleagues, customers, and partners. We can use Tableau to blend it with other data, and we can keep our data up to date automatically.
8. What are Filters? How many types of Filters are there in Tableau?
A Filter restricts unnecessary data; it shows the exact data we want. Basically, Filters are of three types:
- Quick Filter
- Context Filter
- Datasource Filter
9. What is aggregation and disaggregation of data?
Suppose, we have data like below:
Eid Ename Salary Dept
1.abc 2000 java
2.bbc 3000 .net
3.Krishna 2500 java
5.Vamshi 3000 mainframes
1.abc 1000 testing
2.bbc 3000 tableau
4.Madhu 7000 testing
vanshi 9000 tableau
1 abc 11000 Mainframes
2 bbc 13000testing
3 krishna 15000 java
4 Madhu 17000 .nte
5 vamshi 19000.net
Aggregation: To display aggregate data
Sum/avg salary by each individual employee
Drag ename on column and salary on rows, and we will get the sum (salary) of each and individual employee
Now, change the measure type as Avg
Choose salary option: choose measure types as ‘Avg’
Disaggregation: To display each and every transaction
When we look at the aggregated data in the views above, each bar represents all transactions for a specific employee summed up or averaged into a single value. Now, say, we want to see the individual salary transactions for each employee. We can create a view like that by selecting Analysis > Aggregate Measures.
10. How to remove the Show All option from a Tableau Auto Filter?
Right-click on Filter > Customize > uncheck the Show All option
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11. Can we use non-used columns (columns that are not used in reports but used in data source) in Tableau Filters?
Yes! For example, in a data source, if we have columns like EmpID, EmpName, EmpDept, EmpDsignation, EmpSalary, and in reports we are using EmpName on columns and EmpSalary on rows, we can use EmpDesignation on Filters.
12. What is the benefit of Tableau Extract file over the live connection?
Extract can be used anywhere without any connection, and we can build our own visualizations without connecting to a database.
13. What is the different between twb and twbx file extensions. Please explain.
The file extension .twb is a live connection; it points to the data source. The user receiving .twb needs permission to access the said data source and no data is included.
On the other hand, .twbx takes the data offline and stores it as a package or zip-like file, thereby eradicating the need for permissions.
14. How to combine two Excel files with the same fields but different data (different years)?
Suppose, we have five different Excel files (2007.xls, 2008.xls, … 2011.xls) with the same fields (film name, genre, budget, rating, profitability, etc.) but with data of different years (2007 to 2011). Can someone tell me how can I combine the film name, genre, and profitability so that I can see the visualization of 2007 to 2011 in a single chart?
15. What is the maximum number of tables we can join in Tableau?
We can join a maximum of 32 tables; it is not possible to combine more than 32 tables.
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Intermediate Interview Questions
16. What is the difference between joining and blending in Tableau?
Joins in Tableau
Suppose, our client is in the healthcare domain and using SQL Server as their database. In SQL Server, there may be many Tableau-like Claims Tables, Rejected Claims Table, Customer Table, etc. Now, the client wants to know the customer-wise claims and the customer-wise rejected claims table using the Joins. Join is a query that combines the data from two or more tables by making use of the Join condition.
We can join a maximum of 32 tables; it is not possible to combine more than 32 tables.
In Tableau, Joins can be performed in two ways:
- By making use of common columns
- By making use of common data types
If we create Joins on the fields, in Tableau, all the table names are suffixed with $. While performing Joins on multiple tables, always go with the less amount of data tables, so that we can improve the performance.
In Tableau, Joins are divided into two types:
In the Join condition, if we are using equality (‘=’) operator, then such a kind of join is called Equi Join. Equi Join is further divided into three types:
- Inner Join: Inner Join will load the only matching records from both tables. Below is the Inner Join condition:
Tableaa.id = Tableb.id
Outer Join: Outer Join is further divided into three types:
Left Outer Join: Displays the complete data from the left table + matching records from the right
Right Outer Join: Displays the complete data from the right table + matching records from the left
Full Outer Join: Loads the complete data from the left table and the right table
Table A full outer join Table B ON tablea.id= tableb.id
Self-join: If we are performing Join to a table with itself such a kind of Join is called a Self-join.
In the Join condition, if we are using operators apart from the equality (‘=’) operator (such as, <, >, <=, >=, and =!), then such a kind of Join is called Non-equi Join.
Data Blending in Tableau
Consider the same client. Suppose, they are operating their services in Asia, Europe, NA, and so on, and they are maintaining Asia data in SQL, Europe data in SQL Server, and NA data in MySQL.
Now, our client wants to analyze their business across the world in a single worksheet. In this case, we can’t perform a Join. Here, we have to make use of the data blending concept.
Normally, in Tableau, we can perform the analysis on a single data server. If we want to perform the analysis of data from multiple data sources in a single sheet, then we have to make use of this new concept called data blending.
Data blending mixes the data from different data sources and allows users to perform the analysis in a single sheet. ‘Blending’ means ‘mixing’ and when we are mixing the data sources, then it is called data blending.
Rules to Perform Data Blending
In order to perform data blending, there are a few rules:
- If we are performing data blending on two data sources, these two data sources should have at least one common dimension.
- In that common dimension, at least one value should be matching.
In Tableau, we can perform data blending in two ways.
- Automatic way: Here, Tableau automatically defines the relationship between the two data sources based on the common dimensions and based on the matching values, and the relationship is indicated in orange.
- Custom or Manual way: In the manual or custom way, the user needs to define the relationship manually.
Data Blending Functionality
- All the primary and secondary data sources are linked by a specific relationship.
- While performing data blending, each worksheet has a primary connection, and optionally it might contain several secondary connections.
- All the primary connections are indicated in blue in the worksheet and all the secondary connections with an orange-colored tick mark.
- In data blending, one sheet contains one primary data source and it can contain n number of secondary data sources.
17. What are Dimensions and Facts?
- Dimensions are nothing but the descriptive text columns. Example: product name, city, etc.
- Facts are the measures (numerical values). Example: sales, profit, etc.
18. Can we place an Excel file in a shared location and use it to develop a report and refresh it in regular intervals?
Yes, we can do it, but for better performance we have to use Extract.
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19. What is the difference between heat map and treemap?
- A heat map is a great way to compare categories using color and size. In this, we can compare two different measures.
- A treemap is a very powerful visualization, particularly used for illustrating hierarchical (tree-structured) data and for visualizing a part of or a whole relationship.
20. What is dual axes?
To display two measures in one graph, Tableau uses dual axes.
Related Article: How To Use Tab admin For Administrative Task Automation In Tableau?
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21. What is blended axis?
Here, multiple measures are shown in a single axis and all the marks are shown in a single pane.
- Drag a dimension in a column
- Drag the first measure in the column
- Drag the second measure in the existing axis
22. What makes Tableau stand out?
Tableau stands out for several reasons:
- First, most of the BI tools are pricey, but Tableau has a free offering (Tableau Public) and a very popular (also free) academic distribution.
- Tableau is well recognized by firms like Forrester Research to be one of the most easy-to-use and agile products currently available.
- On the other hand, unlike some of the other BI tools, Tableau is not a complete technology stack; It is mostly useful for visualization and analytics. We will need other products in addition to Tableau for heavier enterprise data ETL, maintenance, storage, etc.
23. How do we do testing in Tableau?
We can’t perform testing in Tableau. It is a data visualization software.
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24. Can you get values from two different sources as a single input into parameter?
Tableau currently does not support the multi-valued parameters. Case Study: The “dynamic parameter with a blend” technique can be used to highlight a single value, but not multiple values because of the way it works. As Tableau parameters are not dynamic, we cannot “filter” the list of values at runtime.
25. How do we use parameters in Tableau?
We can use parameters with filters, calculated fields, actions, measure-swaps, changing views, and auto-updates.
26. What is the use of the new custom SQL query in Tableau?
Custom SQL query is written after connecting to data for pulling the data in a structured view. For example, suppose, we have 50 columns in a table, but we need just 10 columns only. So instead of taking 50 columns, we can write a SQL query. The performance will increase.
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27. What are the differences between Tableau and other traditional BI tools?
Tableau provides easy to use, best in class, visual analytic capabilities, but it does not help with plumbing (data foundation). We could, for example, marry SQL Server with Tableau to get the complete package. Tableau licenses are relatively expensive if we are looking to scale.
Traditional BI can handle it all but with significant upfront costs, higher consulting, hardware, and software costs. Among the mega-vendors, only Microsoft can provide a reasonable value proposition. Open-source vendors like Pentaho and Jaspersoft do not have an abundant-enough talent pool, yet.
28. What are the similarities and differences between Tableau and Palantir?
Palantir and Tableau are very different. Palantir has its roots in large data computer science problems involving security, payments, fraud detection, and the like. Its customers/investors include PayPal, CIA, and others.
Tableau is a visualization player, with roots in Stanford University Research. Its Visual Query Language (VizQL) allows users to build visualizations on top of the standard data warehouses or spreadsheets.
29. How to create cascading filters without using context filter?
Here, say, we have Filter1 and Filter2. Based on Filter1, we need to use Filter2 on the data. For example, consider Filter1 as ‘Country’ and Filter2 as ‘States.’
Let’s choose Country as ‘India’ and hence Filter2 should display only the states of India.
Choose options of Filter2 states:
select option of ‘Only relevant values’
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30. Is Tableau good for a strategic acquisition?
Yes, for sure! It gives us data insights much more than the others. It helps us plan and point the anomalies and improvise our process for betterment.
Check out this insightful video on Tableau Training for Beginners:
31. How to display the top five and the last five sales in the same view?
Using filters or calculated fields, we can display the top five and the last 5 sales in the same view.
32. Suppose, without using a line/bar chart, I want to design a view to show the region-wise profit and sales. How should I go about doing it? Explain.
- Generate a map using cities
- Then, drag the profit and sales to Details
- Add the state as Quick filter
33. Design a view in a map such that if a user selects any state, the profit and sales in the cities under that state would show up.
If we want to show the sales and profit of each and every city under the states in the same worksheet, first, we should have State, City, Sales, and Profit fields in our dataset.
- Double-click on the State field
- Drag City and drop into Marks card (under the State field)
- Drag Sales and drop into Size
- Drag Profit and drop into Color
- Click on Size legend and increase the size (75%)
- Right-click on the State field and select Show Quick filter
- Select any state and check whether we got the required view or not.
- In this, the view size indicates the number of sales and the color indicates the profit values.
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34. How to add custom color in Tableau?
Create Custom Color code in ‘Preferences.tps’
Documents » My Table Repository » Preferences.tps
Then, add custom color code
Note: In Tableau 9.0, we have a color picker option.
35. How can we combine a database and the flat file data in Tableau Desktop?
- Connect data twice, once for database tables and then for the flat file. The Data->Edit Relationships
- Give a Join condition on the common column from DB tables to the flat file
36. What does Tableau do?
Tableau’s major goal is to help people see and understand data. Its software products put the power of data into the hands of everyday people, allowing a broad population of business users to engage with their data, ask questions, solve problems, and create values.
Related Article: Learning To Leverage Tabcmd In Tableau
37. What is Tableau Public?
Tableau Public is a free service that lets anyone publish interactive data to the web. Once on the web, anyone can interact with the data, download it, or create their own visualizations for it. No programming skills are required here. We can also check out the gallery to see some of the things people have been doing with it.
38. What is data modeling?
Data modeling is the analysis of data objects that are used in a business or other context and the identification of the relationships among these data objects. Data modeling is the first step in performing object-oriented programming.
39. What is your daily work process in Tableau?
I think we all work on different projects using Tableau, so the work begins from understanding the requirement, and then we have to get the required data, create a storyboard, create visualizations in Tableau, and then present it to the client for review.
40. What is parameters in Tableau? How do they work?
Parameters are dynamic values that can replace constant values in calculations, and they can serve as filters.
Advanced Interview Questions
41. How does Tableau work with huge datasets?
Tableau’s performance is based on the performance of the data source. If the data source takes more time to execute a query, then Tableau must wait up to that time.
42. How will you publish and schedule a workbook in Tableau Server?
- First, create a schedule for a particular time and then create Extract for the data source and publish the workbook on the server.
- Before we publish it, there is an option called ‘Scheduling and Authentication’. Click on that and select the schedule from the drop-down and then publish. Also publish data source and assign the schedule. This schedule will automatically run for the assigned time and the workbook will get refreshed on a regular basis.
43. Distinguish between Parameters and Filters.
- Parameters are dynamic values that can replace constant values in calculations. Parameters can serve as Filters as well.
- Filters, on the other hand, are used to restrict the data based on a condition that we have mentioned in the Filters shelf.
44. How to view a SQL generated by Tableau Desktop?
Tableau Desktop Log files are located in C:UsersMyDocumentsMy Tableau Repository. If we have a live connection to the data source, we need to check the log.txt and tabprotosrv.txt files. If we are using Extract, have to check the tdeserver.txt file. The tabprotosrv.txt file often shows detailed information about queries.
Related Article: What Kinds Of Tasks Can Be Done With Tabcmd In Tableau?
45. What is Page shelf?
Page shelf is a powerful part of Tableau that we can use to control the display of the output and the printed results of the output.
46. What are the major differences between Tableau 7.0 and Tableau 8.0?
- New visualizations are introduced like treemap, bubble chart, and box and whisker plot.
- We can copy worksheet directly from one workbook to another workbook
- Introduced R script
47. How to create filled maps?
- Step 1: Build a Map View, double-click on a geographic field such as State, Area Code, Zip Code, etc.
- Step 2: Select the Filled Map Mark Type The Automatic mark type will show this type of view as circles over a map. On the Marks card, select Filled Map to color the geographic areas.
- Step 3: Drag a Field to the Color shelf, define how the locations are colored by dragging another field to the Color shelf.
48. Does a parameter have its own drop-down list?
Yes, it may have its own drop-down list. The entries we make in the Parameter while creating it can be viewed as items in the drop-down list.
49. How to rectify SQL performance for developed dashboards?
After the creation of dashboards, if we get a problem from the SQL side it means Custom SQL….How to Rectify the SQL performance from custom SQL.
50. How is data blending different from data joining?
Data blending is the combining of data from two or more different sources. We can combine the data between two sources, such as Oracle, SQL Server, Excel, and others.
Consider the admission data given in a relational database and the admission target data given in an Excel spreadsheet. Now, to compare the actual admissions with the target admissions, we can perform data blending. Here, we will blend the data based on some common dimensions of both sources to access the measure of the Admissions target. We list the two sources involved in data blending as the primary and secondary sources of the data. A left join is performed between the primary data source and the secondary data source, wherein all the data rows from the primary data source and only the matching data rows from the secondary data source are fetched.
Each data source in data blending includes its own collection of dimensions and measures. Data blending is useful when combining data from a variety of sources.
Data joining, on the other hand, is also combining data but from two or more tables or sheets within the same data source.
Combining two tables from the same SQL Server or Oracle Database or DB2 or any other data source. Combining two worksheets or more in the same Excel package will also fall under data joining.
Data joining is useful when combining data from a single source with several tables, sheets, or others.
51. Is it possible to store a huge amount of data in a memory engine using Tableau? If yes, how can we achieve that?
Yes, it is possible.
Yet, this question doesn’t have a straight answer since we can store massive amounts of data differently on the basis of the different configurations of Tableau Server implementation (such as 8 cores, 16 cores, etc.). Not just if Hyper is used or not, but other factors like server memory may also affect the amount of the data we can store.
Note: When dumping large amounts of data on Tableau Server, we have to make sure that this data volume should not affect the dashboard’s performance and the response time, and also, the processing time for extracts. This is where Tableau’s efficiency is enhanced by Hyper.
52. How is Tableau different from traditional reporting/BI tools?
Traditional BI solutions are powerful and can provide scaling and reliability. Various well-established software firms have endorsed them. These solutions provide ample security for data. Although, they need good BI technical knowledge and skills to work with them. Oracle BI and Qlikview are just two simple tools used among them.
Tableau is one of the top BI tools used in the industry today, providing easy operation and understanding without much knowledge of BI competencies. It has simple drag-and-drop functionality and a smart way to categorize the fields of data. However, in Tableau Public, data security is not provided, while in the Professional version, security is enabled.
53. What is the difference between INDEX and RANK in Tableau?
RANK and INDEX come under table calculations in Tableau. INDEX mainly deals with a record’s physical position. Incremental numbers are assigned according to the record’s physical order.
Whereas, RANK deals with a record’s value. The highest value gets the highest rank and the lowest value gets the lowest rank.
54. How to automate reports in Tableau?
We will see the option to schedule reports when uploading a report on Tableau Server. We can click on this button to set the time to refresh the data.
55. Suppose, my license expires today. Can my users be able to view the dashboards or workbooks that I published in the server earlier?
If our server license expires today, our user name on the server will have the role ‘unlicensed’ which means that we cannot access but others can. The Site Admin can ‘Change Ownership’ to another person, so Extracts if enabled do not fail.
56. Assume that I am using Tableau Desktop and have a live connection to Cloudera Hadoop data. I need to press F5 to refresh the visualization. Is there any way to automatically refresh the visualization every x minutes instead of pressing F5 everytime?
Here is how we can refresh the dashboard in every 3 seconds:
- Replace api src and the server URL with ours. The interval below is for 3 seconds.
Related Article: What Are The Rapid-fire Analysis At A Public Utility In Tableau?
57. What is Tableau Desktop?
Tableau Desktop is based on breakthrough technology from Stanford University that lets us drag and drop to analyze data. It is a great data visualization tool, with which we can connect to data in a few clicks, then visualize and create interactive dashboards with a few more clicks.
58. What are the differences between Tableau, GoodData, and the other traditional BI tools (BusinessObjects, etc.)?
We can talk about the features and functionalities of them for days, but at a high level, there are four major differences:
- Speed: How fast can we get up and running with the system, answer questions, design and share dashboards, and then change them? This is where systems like Tableau and GoodData are far better than the old-school Business Intelligence tools like BusinessObjects or Cognos. Traditional systems took months or years to implement, with costs running to millions. Tableau has a free trial version that gets installed in minutes, and GoodData is cloud-based, so they are faster to implement by orders of magnitude. They are also faster in giving results: traditional BI requires IT and developers to make any changes to reports, so business users are mostly stuck in a queue waiting to get anything done. Tableau and GoodData provide more of a self-service experience.
- Analysis: This is where Tableau excels. It has a powerful and flexible drag-and-drop visualization engine based on some technology from Stanford. GoodData and traditional BI tools typically provide some canned reports but changing them requires significant time and money.
- Data layer: This is where the three options are the most different:
- GoodData requires us to move our data to its cloud. Traditional BI typically requires us to move our data to its data warehouse. On the other hand, Tableau connects to a variety of existing data sources and also provides a fast in-memory data engine, essentially a local database. Since most enterprises have their data stored all over the place, this provides the most convenient choice and lets companies use the investment they’ve already made.
- Enterprise readiness: Traditional BI and Tableau do well here, with enterprise-level security and high scalability.
Related Article: Aggregating Disparate Data Sources At A Large University In Tableau
59. What is Tableau?
Tableau is the Business Intelligence software that allows anyone to easily connect to data and then visualize and create interactive and sharable dashboards. It’s easy enough that any Excel user can learn it, but powerful enough to satisfy even the most complex analytical problems. With tableau, securely sharing the findings with others only takes seconds.
60 What is Tableau Server?
Tableau Server is a browser- and mobile-based insight anyone can use. We can easily publish dashboards with Tableau Desktop and share them throughout our organization. It’s easy to set up and even easier to run.
61. Explain the integration of Tableau with R.
R is a popular open-source environment for statistical analysis. Tableau Desktop can now connect to R through calculated fields and take advantage of R functions, libraries, and packages, and even the saved models. These calculations dynamically invoke the R engine and pass values to R via the Reserve package and they are returned to Tableau.
- Tableau Server can be configured to connect to an instance of Rserve through the tabadmin utility, allowing anyone to view a dashboard containing the R functionality.
- Combining R with Tableau gives us the ability to bring deep statistical analysis into drag-and-drop visual analytics.
62. What is the difference between the quick filter and the normal filter in Tableau?
Quick filter is used to view the filtering options and can be used to select options. Whereas, the Normal filer is something with which we can limit the options from the list or use some conditions to limit the data by field or value.