Important interview questions with answers

1. What is tableau?
• Tableau is a business intelligence software.
• It allows anyone to connect to respective data.
• It visualizes and creates interactive and shareable dashboards.
2. What are the different Tableau Products and what is the latest version of Tableau?
The tableau product family can be shown as follows
Tableau Desktop:
• It is a self service business analytics and data visualization software that anyone can use. It
translates pictures of data into optimized queries. With tableau desktop, the user can
directly connect to data from the data warehouse for live up-to date data analysis. The user
can also perform queries without writing a single line of code. He or she can import all data
into Tableau’s data engine from multiple sources & integrate altogether by combining
multiple views in an interactive dashboard.
Tableau Server:
• It is more of an enterprise level Tableau software. The user can publish dashboards with
Tableau Desktop and can share them throughout the organization with web-based Tableau
server. It leverages fast databases through live connections.
Tableau Online:
• This is a hosted version of Tableau server which helps to make business intelligence faster
and easier than before. The user can publish Tableau dashboards with Tableau Desktop and
share them with colleagues.
Tableau Reader:
• It’s a free desktop application that enables the user to open and view visualizations that are
built in Tableau Desktop. He or she can filter, drill down data but cannot edit or perform any
kind of interactions.
Tableau Public:
• This is a free Tableau software which the user can use to make visualizations but he or she
needs to save the workbooks or worksheets in the Tableau Server which can be viewed by
anyone.
3. What are the different datatypes in Tableau?
The following data-types are supported in tableau
4. What are Measures and Dimensions?
• Measures are numeric metrics or measurable quantities of data, which can be analysed by
dimension table. Measures are stored in a table that contain foreign keys referring uniquely
to the associated dimension tables. The table supports data storage at atomic level and thus,
allows more number of records to be inserted at a time. For instance, a Sales table can have
product key, customer key, promotion key and items sold referring to a specific event.
• Dimensions are the descriptive attribute values for multiple dimensions of each attribute,
defining multiple characteristics. A dimension table having reference of a product key form
the table and can consist of a product name, product type, size, colour description and so on
5. What is the difference between .twb and .twbx extension?
• A .twb is an xml document which contains all the selections and layout that the user has
made in his or her Tableau workbook. It does not contain any data.
• A .twbx is a ‘zipped’ archive containing a .twb and any external files such as extracts and
background images
6. How many maximum tables can you join in Tableau?
A maximum of 32 tables can be joined in Tableau.
7. What are the different connections you can make with your dataset?
We can either connect live to our data set or extract data onto Tableau.
• Live connection: Connecting live to a data set leverages its computational processing and
storage. New queries will go to the database and will be reflected as new or updated within
the data.
• Extract: An extract will make a static snapshot of the data to be used by Tableau’s data
engine. The snapshot of the data can be refreshed on a recurring schedule as a whole or
incrementally append data. One way to set up these schedules is via the Tableau server.
The benefit of Tableau extract over live connection is that extract can be used anywhere
without any connection and the user can build his or her own visualization without
connecting to database.
8. What are shelves?
They are Named areas to the left and top of the view. You build views by placing fields onto
the shelves. Some shelves are available only when you select certain mark types.

9. What are sets?

• Sets are custom fields that define a subset of data based on some conditions.
• A set can be based on a computed condition, for example, a set may contain
customers with sales over a certain threshold.
• Computed sets update as the users’ data changes.
• Alternatively, a set can be based on specific data point in the users’ view.
10. What are groups?
• A group is a combination of dimension members that make higher level categories. For
example, if the user is working with a view that shows average test scores by major, he or
she may want to group certain majors together to create major categories.
11. What is a hierarchical field?
• A hierarchical field in tableau is used for drilling down data. It means viewing the data at a
more granular level.
12. What is Tableau Data Server?
• Tableau server acts a middle man between Tableau users and the data. Tableau Data Server
allows us to upload and share data extracts, preserve database connections, as well as reuse
calculations and field metadata. This means any changes we make to the data-set, calculated
fields, parameters, aliases, or definitions, can be saved and shared with others, allowing for
a secure, centrally managed and standardized dataset. Additionally, we can leverage our
server’s resources to run queries on extracts without having to first transfer them to our
local machine.
13. What is Tableau Data Engine?
• Tableau Data Engine is a really cool feature in Tableau. Its an analytical database designed
to achieve instant query response, predictive performance, integrate seamlessly into
existing data infrastructure and is not limited to load entire data sets into memory.
14. What are the different filters in Tableau and how are they different from each other?
• Normal Filter is used to restrict the data from database based on selected dimension or
measure. A Traditional Filter can be created by simply dragging a field onto the ‘Filters’
shelf.
• Quick filter is used to view the filtering options and filter each worksheet on a dashboard
while changing the values dynamically (within the range defined) during the run time.
• Context Filter is used to filter the data that is transferred to each individual worksheet.
When a worksheet queries the data source, it creates a temporary, flat table that it uses to
compute the chart. This temporary table includes all values that are not filtered out by
either the Custom SQL or the Context Filter.
15. How to create a calculated field in Tableau?
• Click on the drop down to the right of Dimensions on the Data pane and select “Create >
Calculated Field” to open the calculation editor.
• Name the new field and then create a formula.
16. What is a dual axis?
• Dual Axis is an excellent phenomenon supported by Tableau that helps users view two
scales of two measures in the same graph. Many websites like Indeed.com and other make
use of dual axis to show the comparison between two measures and their growth rate in a
septic set of years
17. What is the difference between a tree map and heat map?
• A heat map can be used for comparing categories with colour and size. With heat maps, we
can compare two different measures together.

A tree map also does the same except it is considered a very powerful visualization
as it can be used for illustrating hierarchical data and part-to-whole relationships.
18. What is the difference between joining and blending in Tableau?
• Joining term is used when we are combining data from the same source, for example, worksheet in
an Excel file or tables in Oracle database
• While blending requires two completely defined data sources in our report.
19. What are Extracts and Schedules in Tableau server?
• Data extracts are the first copies or subdivisions of the actual data from original data sources.
• The workbooks using data extracts instead of those using live DB connections are faster since the
extracted data is imported in Tableau Engine.
• After this extraction of data, users can publish the workbook, which also publishes the extracts in
Tableau Server.
• However, the workbook and extracts won’t refresh unless users apply a scheduled refresh on the
extract.
• Scheduled Refreshes are the scheduling tasks set for data extract refresh so that they get refreshed
automatically while publishing a workbook with data extract.
• This also removes the burden of republishing the workbook every time the concerned data gets
updated
20. How to view underlying SQL Queries in Tableau?
Viewing underlying SQL Queries in Tableau provides two options:
• Create a Performance Recording to record performance information about the main events that the user
interacts with workbook. Users can view the performance metrics in a workbook created by Tableau.
• Help -> Settings and Performance -> Start Performance Recording Help -> Setting and Performance -> Stop
Performance Recording.
• Reviewing the Tableau Desktop Logs located at C:UsersMy DocumentsMy Tableau Repository.
• For live connection to data source, user can check log.txt and tabprotosrv.txt files.
• For an extract, user can check tdeserver.txt file.
21. How to do Performance Testing in Tableau?
• Performance testing is again an important part of implementing tableau.
• This can be done by loading Testing Tableau Server with TabJolt, which is a “Point and Run” load generator
created to perform QA.
• While TabJolt is not supported by tableau directly, it has to be installed using other open source products.
22. How to remove ‘All’ options from a Tableau auto-filter?
• The auto-filter provides a feature of removing ‘All’ options by simply clicking the down
arrow in the auto-filter heading.
• The user can scroll down to ‘Customize’ in the dropdown and then uncheck the ‘Show “All”
Value’ attribute.
• It can be activated by checking the field again
23. How to add Custom Color to Tableau?
• Adding a Custom Color refers to a power tool in Tableau.
• The user needs to restart Tableau desktop once he or she saves.tps file. From the Measures
pane, the user needs to drag the one to which the user wants to add color to Color.
• From the color legend menu arrow, the user needs to select Edit Colors.
• When a dialog box opens, the user can select the palette drop-down list and customize as
per requirement.
24. What is TDE file?
• TDE is a Tableau desktop file that contains a .tde extension. It refers to the file that contains
data extracted from external sources like MS Excel, MS Access or CSV file.
• There are two aspects of TDE design that make them ideal for supporting analytics and data
discovery.
• Firstly, TDE is a columnar store.
• The second is how they are structured which impacts how they are loaded into memory and
used by Tableau. This is an important aspect of how TDEs are “architecture aware”.
• Architecture-awareness means that TDEs use all parts of the computer memory, from RAM
to hard disk, and put each part to work what best fits its characteristics.
25. Mention whether you can create relational joins in Tableau without creating a new
table?
• Yes, it is possible to create relational joins in tableau without creating a new table.
26. How to automate reports?
• We need to publish report to tableau server
• While publishing the user can find one option to schedule reports.
• The user just needs to select the time when he or she want to refresh data.
27. Explain when would you use Joins vs. Blending in Tableau?
• If data resides in a single source, it is always desirable to use Joins.
• When the data is not in one place blending is the most viable way to create a left join like
the connection between the primary and secondary data sources.
28. What is default Data Blending Join?
• Data blending is the ability to bring data from multiple data sources into one Tableau view,
without the need for any special coding.
• A default blend is equivalent to a left outer join.
• However, by switching which data source is primary, or by filtering nulls, it is possible to
emulate left, right and inner joins.
29. What do you understand by blended axis?
• In Tableau, measures can share a single axis so that all the marks are shown in a single
pane.
• Instead of adding rows and columns to the view, when the user blends measures there is a
single row or column and all of the values for each measure is shown along one continuous
axis.
• We can blend multiple measures by simply dragging one measure or axis and dropping it
onto an existing axis.
30. What is story in Tableau?
• A story is a sheet that contains a sequence of worksheets or dashboards that work together
to convey information.
• We can create stories to show how facts are connected, provide context, demonstrate how
decisions relate to outcomes, or simply make a compelling case.
• Each individual sheet in a story is called a story point.
31.How to create stories in Tableau?
There are many ways to create story in Tableau.
Each story point can be based on a different view or dashboard, or the entire story can be based on the same
visualization, just seen at different stages, with different marks filtered and annotations added.
We can use stories to make a business case or to simply narrate a sequence of events. The steps are as follows:
• Click on the New Story tab.
• In the lower-left corner of the screen, the user needs to choose a size for his or her story from one of the
predefined sizes, or the user can set a custom size, in pixels.
• By default, the story gets its title from its sheet name. To edit it, the user can double-click on the title. He or
she can also change your title’s font, color, and alignment and can further click on apply to view the changes.
• To start building a story, the user needs to drag a sheet from the Story tab on the left and drop it into the
centre of the view
• The user then needs to click on Add a caption to summarize the story point.
• To highlight a key takeaway for your viewers, the user can drag a text object over to the story worksheet and
type any comment.
• To further highlight the main idea of this story point, the user can change a filter or sort on a field in the view,
then save these changes by clicking on Update above the navigator box.
32. What is the DRIVE Program Methodology?
• Tableau Drive is a methodology for scaling out self-service analytics.
• Drive is based on best practices from successful enterprise deployments.
• The methodology relies on iterative, agile methods that are faster and more effective than
traditional long-cycle deployment.
• A cornerstone of this approach is a new model of partnership between business and IT.
33. How to use group in calculated field?
• By adding the same calculation to ‘Group By’ clause in SQL query or creating a Calculated
Field in the Data Window and using that field whenever the user wants to group the fields.
• Using groups in a calculation: It is not possible for the user to reference ad-hoc groups in a
calculation.

• Blending data using groups created in the secondary data source: Only calculated groups
can be used in data blending if the group was created in the secondary data source.

• Use a group in another workbook: We can easily replicate a group in another workbook by
copy and pasting a calculation.
34. Mention what is the difference between published data sources and embedded data
sources in Tableau?
• The difference between published data source and embedded data source is that,
• Published data source: It contains connection information that is independent of any
workbook and can be used by multiple workbooks.
• Embedded data source: It contains connection information and is associated with a
workbook.

35. Mention what are different Tableau files?

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