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Tableau Interview Questions

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Tableau Interview Questions

If you're looking for Tableau Interview Questions for Experienced or Freshers, you are at right place. There are lot of opportunities from many reputed companies in the world. According to research Tableau has a market share of about 16.2%. So, You still have opportunity to move ahead in your career in Tableau Analytics. Mindmajix offers Advanced Tableau Interview Questions 2019 that helps you in cracking your interview & acquire dream career as Tableau Developer.

Q1) What is Tableau?

Tableau is easily deployable, highly scalable, and efficient performing framework. It is a data analytics tool which develops interactive and efficient visualizations of data in forms of dashboards. It has an attractive and user-friendly interface.

Q2) Please name out the products offered by Tableau and give a small brief for each of them

Tableau has 4 main products.

  • Tableau Prep : Tableau Prep is responsible for preparing data for analysis. This tool provides 3 coordinated views which provide us with a complete picture of data.
  • Tableau Desktop: Tableau Desktop is the place where the analysis happens. It has powerful drag and drop analytics which is very easy to use. Through desktop, you get your data insights quickly.
  • Tableau Online: Tableau Online is a secure and scalable self-service analytics cloud tool. You can use it anywhere, anytime. It has removed the requirement for IT infrastructure and support.
  • Tableau Server: From small to large enterprises, Tableau server is used for fulfilling their BI requirements. This is an on-premise solution. This tool can take data from anywhere and share across organization through desktop or mobile browsers. There are also android and iPhone apps available to do so.

Q3) Give a brief about tableau dashboard

Tableau dashboard is a group of various views which allows you to compare different types of data simultaneously. Data sheets and dashboards are connected and any modification in data directly reflects on dashboards. It is the most efficient approach to visualize the data and analyze it.

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Q4) State available data types in Tableau

Tableau supports below data types.

Data Type Meaning Examples
String Character Sequence. Enclosed in ''. Tableau', 'World'
Number (Whole) Integers 9
Number (decimal) Floating values. 123.45
Boolean They are logical values. TRUE, FALSE
Date Date "02/01/2015"
Date & Time Date and Time 01 January 2019 05:55:00 PM
Geographic Values Geographical Values India, Italy, Canada

Q5) Differentiate parameters and filters in Tableau

Filters are the simpler and straightforward feature of Tableau. It applies on dimension or measure directly. For example, to only show Gujarat or Karnataka in a State dimension, we can apply filter on that. In Tableau, there are multiple UI options available for filters like radio buttons, drop down lists, check boxes, sliders and more. Filters on sheets are also available in Tableau.

Parameters are like variables. They are complex and more powerful. Like variable, parameter can be used in calculations. So, that means, it only allows single value. Parameters have same UI options except check boxes because check boxes don’t have single value. For example, we can create parameter for interest rate and period, and then we can use these parameters to calculate interest and principal payments.

Q6) How many types of filters are available in Tableau? Explain

Filters are used to provide the correct information to viewers after removing unnecessary data. There are various types of filters available in Tableau.

  • Extract Filters – Extract filters are used to apply filter on extracted data from data source. For this filter, data is extracted from data source and placed into Tableau data repository.
  • Datasource Filters – Datasource filters are same as extract filters. They also work on extracted dataset. But, the only difference is it works with both live and extract connection.
  • Context Filters – Context Filters are applied on the data rows before any other filters. They are limited to views, but they can be applied on selected sheets. They define Aggregation and Disaggregation of data in Tableau
  • Dimension Filters – Dimension filters are used to apply filters on dimensions in worksheets. Dimension filters are applied through the top or bottom conditions, formula and wildcard match.
  • Measure Filters – Measure filters are applied on the values present in the measures.

Q7)  Explain Tableau File Extensions

The below ones are few extensions in Tableau:

  • Tableau Workbook (.twb)
  • Tableau Data extract (.tde)
  • Tableau Datasource (.tds)
  • Tableau Packaged Datasource (.tdsx)
  • Tableau Bookmark (.tdm)
  • Tableau Map Source (.tms)
  • Tableau Packaged Workbook (.twbx) – zip file containing .twb and external files
  • Tableau Preferences (.tps)

Checkout Tableau Tutorials

Q8) Are there any limitations of parameters in Tableau? If yes, give details

Tableau dashboard allows representation of parameters in four ways only. They don’t allow any multiple values like a filter can do. They only allow a single value.

Q9) Define Page Shelf in Tableau?

Page shelf breaks the views into series of pages. It displays alternate view on each page. Due to this feature, you can analyze the effect of each field into rest of the data in view. 

Q10) Differentiate between Tiled and Floating in dashboards?

In tiled layout, items don’t overlap. Layout will be adjusted according to dashboard size. In Floating layout, items can be placed on some other layers. Floating items can have fixed position and size.

[Related Article: The right way to build a dashboard]

Q11) Define story in Tableau?

Story can be defined as a sheet which is a collection of series of worksheets and dashboards conveying information. Story can be used to show the connection between facts and outcomes’ relations to decisions. Story can be published to web or can be presented to audience.

Q12) Give an overview for fact and dimension table?

Facts are numeric measures of data. They are stored in fact tables. Fact tables store that type of data which will be analyzed by dimension tables. Fact tables have foreign keys associating with dimension tables.

Dimensions are descriptive attributes of data. Those will be stored in dimensions table. For example, customer’s information like name, number, email will be stored in dimension table.

Q13) State some reasons for low performance of Tableau

  • Filters - filters need to create an extra query and if it used in large numbers and inefficiently then they can reduce the performance. So, it is advised to use filters whenever it is mandatory
  • Live connection - Tableau extract works much better in comparison with live connection.
  • Data sources - a wrong query to a wrong data source can reduce performance. Also data source’s performance can also affect Tableau’s performance.

[Related ArticleAggregating disparate data sources at a large university in tableau]

Q14) State some ways to improve performance of Tableau

  • Use an Extract to make workbooks run faster
  • Reduce the scope of data to decrease the volume of data
  • Reduce number of marks on the view to avoid information overload
  • Try to use integers or Booleans in calculations as they are much faster than strings
  • Hide unused fields 
  • Use Context filters
  • Reduce filter usage and use some alternative way to achieve same result
  • Use indexing in tables and use same fields for filtering
  • Remove unnecessary calculations and sheets

Q15) Explain different connection types in Tableau.

There are 2 connection types available in Tableau.

Extract: Extract is a snapshot of data which will be extracted from data source and put into Tableau repository. This snapshot can be refreshed periodically fully or incrementally. This can be scheduled in Tableau Server.

Live: It creates a direct connection to data source and data will be fetched directly from tables. So, data will be up to date and consistent. But, this also affects access speed.

Q16) Categorize dimensions in Tableau

Dimensions are divided into 9 various categories

Slowly ever-changing Dimension: Value of the dimension changes over an amount of time for slowly ever-changing dimensions.
Example – student of worker

Chop-chop ever-changing Dimension: Value in the dimension is rapidly changing for chop-chop ever-changing dimensions.
Example – Age (It changes every second)

Unchanged Dimension: Values are constant for unchanged dimension.
Example – Traffic Signals

Shrunken Dimension: Set of 1 dimension is termed as Shrunken Dimension.
Example – A week is Shrunken dimension for the month

Junk Dimension: Junk values or unrelated dimensions are termed as Junk Dimension.

Conformed Dimension: If any dimension is provided by various business areas, then such a dimension is termed as Conformed Dimension.
Example – Time (9-5) for any company or hospital or college

Degenerated Dimension: Degenerated dimensions have primary keys only without any matter info.

Role enjoying Dimension: If one dimension is employed in multiple roles, then they are termed as Role enjoying Dimensions. 
Example – Date for e-commerce site order (Date of Order, Date of Shipment, Date of delivery)

Inferred Dimension: Empty dimensions are called inferred dimensions. They are usually used in ETL.
Example – Customer email which he may not enter while submitting any form will be filled as null

Q17) What is VIZQL in Tableau

VIZQL is Visual Inquiry Language. It is a combination of VIZ and SQL. It is like SQL language. But instead of SQL commands, VIZQL language converts data queries into visual images. 

Q18) Tell me possible joins in Tableau

Tableau works same as SQL. So, it supports all joins possible in SQL

  • Left Outer Join
  • Right Outer Join
  • Full Outer Join
  • Inner Join

Q19) How many table joins are possible in Tableau?

32

Q20) Tell me different ways to use parameters in Tableau

  • Filters
  • calculated fields
  • actions
  • measure-swaps
  • changing views 
  • auto updates

Q21) State limitation of context filters in Tableau

Whenever we set a context filter, Tableau generates a temp table which needs refresh each and every time the view is triggered. So, if context filter will be changed, database needs to recompute and rewrite temp table, which in turn slows down the performance.

Q22) What is mark card in Tableau?

There is a card to the left of the view where we can drag fields and control mark properties like color, size, type, shape, detail, label, and tooltip.

Q23) Define published data source

Published data source has connection information in it. It is independent of any workbook and can be accessed by multiple workbooks.

Q24) Explain disaggregation and aggregation of data in Tableau?

Aggregation → The process of summarizing the data and viewing a single numeric value is called aggregation. Example – sum/avg of salary for each employee

Disaggregation →The process of viewing each transaction for analyzing all the measures both dependently and independently. Example – individual salary transactions for each employee.

Q25) Can we see sql generated by Tableau Desktop?

Tableau Desktop log files are places in C:UsersMy DocumentsMy Tableau Repository. In case of live connection to any data source, check the log file “log.txt” and “tabprotosrv.txt” files. In case of extract connection to any data source, check the “tdeserver.txt” file which has detailed information about queries.

Q25) If owner of the published workbooks license expires, then can other users see those workbooks?

If owner of published workbooks license expires then his/her role will change to “Unlicensed”. He/She cannot access those workbooks, but others can. Only site admin can change the ownership of those workbooks.

Q26) Define Heat Map?

Heat map is a graphical representation of data which uses color-coding technique to represent different values of data. As the marks heat up due to its higher value, dark color will be shown on map.

Q26) Define Tree Map

A tree map is a visualization which organizes data hierarchically and shows them as a set of nested rectangles. Size and colors of rectangles are respective to the values of the data points they project. Parent rectangles will be tiled with their child elements.

Q27) Define dual axis

Dual axis is used to show 2 measures in single graph. It allows you to compare 2 measures at once.

Q28) Define blended axis

Multiple measures can share single axis so that all the marks will be shown in a single pane. We can blend measures by dragging the 1st measure on one axis and 2nd on existing axis.

Q29) Can we remove “All” option from auto-filter in Tableau?

Yes, we can. Navigate to filter→ Right click on it→ select customize→ uncheck the option “Show All”

Q30)  Which one is better? Extract or Live connection?

Extract connection is better than live connection because extract connection can be used from anywhere, anytime without connecting to database. We can construct our own visualizations on it irrespective of database connection.

Q31) Tell me something about workbook version controlled in Tableau.

Versioning of workbooks can be done in 2 ways in Tableau.

  • At desktop level, you keep copies of your changes and files, or using 3rd party system like Microsoft TFS.
  • At server level, where you publish the data source and version will be saved in revision history on Tableau Server or Online. Reverting to a previous version is also possible here.

Q32)  Where can we apply global filters?

Global filters can be applied to sheets, stories, and dashboards.

Q33)  Define LOD Expression

LOD Expression stands for Level of Detail Expression. They provide an effective way to compute aggregation at that level of detail which cannot be achieved through visualization.

Q34)  Define shelves and sets

Shelves are defined as named areas places to top and left of the view. Fields will be placed onto shelves to construct a view.

Sets are a compute condition on which dataset will be prepared. Data will be grouped together based on a condition. Fields which is responsible for grouping are known as sets. For example – students having grades more than 70%

Q35) State the components of the dashboard

Dashboard consists of 5 components.

  • Web : it consists of a web page embedded in the dashboard.
  • Horizontal component: it is a horizontal layout container in which we can add objects.
  • Vertical component : it is a vertical layout container in which we can add objects.
  • Image Extract : it allows you to upload an image to dashboard from computer.
  • Text: it is a small wordpad where we can format and edit the text.

Q36) How to add custom color to Tableau?

To add custom color in Tableau, we need to follow below 3 steps

  • Generate custom color code and create it in “Preferences.tps”
  • Navigate to Documents→ My Table Repository→ Preferences.tps
  • Add note for custom color code

Q37) Can we create cascading filters without using context filters?

Cascading filters means filter2 values are dependent on filter1 value. For Example, filter1 is country and if we select “India” for filter1, filter2 values should show all Indian states. This feature we can achieved by using option “Only Relevant Values”.

Q38) How can we display top and bottom 5 of records in a single Tableau view?

To achieve this, we need to create 2 views

  • View1 which contains top 5 records
  • View2 which contains bottom 5 records
  • View3 which is a join of View1 and View2

Q39) Define Bullet graph

Bullet graph is a variant of Bar graph. It is responsible for comparing performance of one measure with other measures.

Q40) Define Gantt chart

Gantt Chart displays the progress of a value over the period. It consists of bars along with time axis. It is a project management tool. Here, each bar is measure of a task in the project framework.

Q41) Define Histogram chart

A histogram chart shows the distribution of continuous information over a certain period of time. This chart helps us to find extreme points, gaps, unusual values, and more concentrated values.

Q41) State few charts which we should not use with valid reasons

Below here are few charts which we should avoid.

  • 3D Charts: Visual representation of numbers in 3D charts will be skewed and it makes difficult to compare and analyze.
  • Pie Charts: Pie charts are not that much accurate as bar charts. In Pie charts, we have areas and angles to compare instead of length in a bar chart. Areas and angles cannot be analyzed with ease.
  • Donut Charts: This is same as Pie chart, but here, we have a hole in the middle to make it look like donut. Due to that hole, we need to compare arc length with other arcs to analyze the values. Comparing arcs length is also a difficult task for our eyes.

[Related Article: Create Pie charts, Scatter Plot, Area Fill charts & Circular View in Tableau]

Q42) Do we have any way to handle null values in Tableau?

Tableau cannot plot null values on axis. So, it will display an indicator at lower right corner of view. Once you click on that indicator, you have options to handle null values. Below are the options available to handle null values.

  • Filter Data – If you choose this option, null values will be filtered out from the view.
  • Show Data at Default Position – It replaces the null value with default value and shows the data at default position on axis. These default values depend on the data type of field. Below here are the defaults of specific data type.
  • Numbers →0 
  • Dates → 12-31-1899
  • Geographic Location → (0,0)
  • Negative Values → 1

Q43) What is Tableau Public?

Tableau Public is an open source and free service which allows anyone to publish the data source and visualizations to web. These visualizations can then be embedded into blogs or web pages. They can also be distributed through email or social media. Moreover, they can be made downloadable by other end users. For Tableau Public, no programming skills are needed. It can be accessed by anyone free of cost.

Q44) Do we have any data limitation in Tableau Public?

Yes, Tableau Public can only allow 10 million rows to users for data visualization.

Q45) Differentiate discrete and continuous data roles in Tableau

Discrete data roles consist of values which are separate and distinct. Discrete data roles can take individual values within a range. For Example – cancer patients in hospital, no. of threads in a sheet, state. Discrete values are displayed as blue icons in data window and blue pills on shelves. Discrete fields can be sorted.

Continuous data roles consist of any value within finite or infinite interval. For Example – age, unit price, order quantity. Continuous values displayed as green icons in data window and green pills on shelves. Continuous fields cannot be sorted.

Q46)  Can we download views or workbooks from server? If yes, in which data formats?

We can download views or workbooks from server. But, data formats available to us depend on the permissions granted by site administrators or content owners.

  • Image: .png format
  • Data: .csv file.

We can also download selected sheets into PDF format, but while generating PDF, web page objects won’t be included.

Q47)  Define performance testing in terms of Tableau

We can check performance of Tableau by the following 2 ways.

  • We can create performance recording to keep track of performance details of main events while interacting with workbooks. Then, these performance metrics can be viewed by user and analyzed. Navigation to start/stop performance recording is Help→Settings and Performance>→ Start Performance Recording Help→ Setting and Performance → Stop Performance Recording
  • Review the logs created by Tableau Desktop. Location for log files is C:UsersMy DocumentsMy Tableau Repository.
  • For live connection, check the log files log.txt and tabprotosrv.txt.
  • For Extract connection, check the log file tdeserver.txt
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