Tableau Interview Questions Set - 1 Released

Intermediate Level

What is TABLEAU?

Tableau is the powerful and fastest visualizing tool that is used in the Business Intelligence(BI) Industry. It simplifies the raw data into an understandable format. Analysis of the data becomes faster with Tableau. The visualizations can be created in the form of dashboards. The visualizations or diagrammatic representation of data can easily be understood by the employees of the organizations who are at different levels.

What is data visualization?

Data visualization means the graphical representation of data or information. We can use visual objects like graphs, charts, bars, and a lot more. Data visualization tools provide an accessible way to see and understand the data easily.

List out 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 (.tbm) - Tableau Map Source (.tms) - Tableau Packaged Workbook (.twbx) – zip file containing .twb and external files. - Tableau Preferences (.tps)

What is the latest version of Tableau Desktop?

Tableau Desktop's latest version is 2022.2

Define LOD Expression?

LOD Expression stands for Level of Detail Expression, and it is used to run complex queries involving many dimensions at the data sourcing level.

Define Heat Map?

A heat map is a graphical representation of data that uses the color coding technique to represent different values of data. As the marks heat up due to their higher value, dark colors will be shown on the map.

Define TreeMap?

TreeMap is a visualization that organizes data hierarchically and shows them as a set of nested rectangles. The 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.

What is the difference between a Heat map and Treemap?

TreeMap Heat MapIt represents the data hierarchically and shows them as a set of nested rectangles. It represents the data graphically which uses multiple colors to represent different values. It is used for comparing the categories with colors, size, and it can also be used for illustrating the hierarchical data and part to whole relationships. It is used for comparing the categories based on color and size. And also it is great in spotting the patterns based on the density of the information. The colors and size of rectangles are respective to the values of the data points When their values are higher or density of records, the data will represent in dark color.

What is a parameter Tableau? And how does it work?

Parameters are dynamic values, we can replace the constant values in calculations.

What are the different data types in Tableau?

Tableau supports below data types.Data TypeMeaningExamplesStringCharacter Sequence. Enclosed in ''.Tableau', 'World'Number (Whole)Integers9Number (decimal)Floating values.123.45BooleanThey are logical values.TRUE, FALSEDateDate"02/01/2015"Date & TimeDate and Time01 January 2019 05:55:00 PMGeographic ValuesGeographical ValuesIndia, Italy, Canada

Give a brief about the tableau dashboard?

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

Define Page Shelf in Tableau?

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

Define the story in Tableau?

The story can be defined as a sheet which is a collection of series of worksheets and dashboards used to convey the insights of data. A story can be used to show the connection between facts and outcomes that impacts the decision-making process. A story can be published on the web or can be presented to the audience.

Give an overview of the fact and dimensions of the table?

Facts are numeric measures of data. They are stored in fact tables. Fact tables store that type of data that 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 the dimensions table. For example, customer’s information like name, number, and email will be stored in the dimension table.

State some ways to improve the performance of Tableau

- Use an Extract to make workbooks run faster - Reduce the scope of data to decrease the volume of data - Reduce the 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 the same result - Use indexing in tables and use the same fields for filtering - Remove unnecessary calculations and sheets

Explain different connection types in Tableau?

There are 2 connection types available in Tableau.

Extract: Extract is a snapshot of data that will be extracted from the data source and put into the 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 the 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.

What are the different Joins in Tableau?

Tableau works the same as SQL. So, it supports all Joins possible in SQL - Left Outer Join - Right Outer Join - Full Outer Join - Inner Join

What is Data Modelling?

Data modeling is the analysis of data objects that are used in a business or other context and also used as identification of the relationships among these data objects. It is the first step of doing object-oriented programming.

Define Dual-axis?

Dual-axis is used to show 2 measures in a single graph. It allows you to compare 2 measures at once. Many websites like indeed use this Dual axis to show the comparisons and growth rate

Define blended axis?

Multiple measures can share in a 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 the 2nd on the existing axis.

Define shelves and sets?

Shelves: Every worksheet in Tableau will have shelves such as columns, rows, marks, filters, pages, and more. By placing filters on shelves we can build our own visualization structure. We can control the marks by including or excluding data. Sets: The sets are used to compute a condition on which the dataset will be prepared. Data will be grouped together based on a condition. Fields which is responsible for grouping are known assets. For example – students having grades of more than 70%.

Explain the limitation of context filters in Tableau?

Whenever we set a context filter, Tableau generates a temp table that needs to refresh each and every time, whenever the view is triggered. So, if the context filter is changed in the database, it needs to recompute the temp table, so the performance will be decreased.

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