BigData / Tableau Interview Questions
1. What is a Tableau workbook?
A Tableau workbook is the main file you create and save your work in when using Tableau Desktop. It's the container that holds everything related to one analysis project. One or more worksheets , each showing a single view or chart. Dashboards , which combine multiple worksheets into one interact...
2. What is Tableau?
Tableau is a visual analytics platform transforming the way we use data to solve problems-empowering people and organizations to make the most of their data. Tableau allows users to connect to various data sources, create interactive dashboards, and generate insightful reports. Tableau is the Bus...
3. What is data visualization?
Data visualization is a way to represent data that is visually appealing and interactive. With advancements in technology, the number of business intelligence tools has increased which helps users understand data, data sets, data points, charts, graphs, and focus on its impact rather than underst...
4. What is a Tableau worksheet?
A worksheet is the basic building block of analysis in Tableau — it's the single-view canvas where you actually build one chart or table by dragging fields onto shelves. Fields from your data source appear as pills in the left-hand pane, split into Dimensions and Measures. Dragging pills on...
5. What is a dashboard in Tableau?
A dashboard combines multiple worksheets, along with text, images, web pages, and interactive controls, into a single unified view — the format most end users actually interact with. Worksheets are dragged onto the dashboard canvas as containers and arranged using tiled or floating layouts....
6. What are the different data connection options available in Tableau?
Tableau offers a myriad of data sources such as local text files, MS Excel, PDFs, JSON or databases and servers like Tableau Server, MySQL Server, Microsoft SQL Server , etc. Categorically, there are two types of data sources that you can connect to in Tableau; To a file and To a server .
7. What are the different datatypes in Tableau?
Tableau supports the following 7 data-types: String values, Number/Integer values, Date values, Date & Time values, Boolean values, Geographic values, and Cluster or mixed values.
8. What is a story in Tableau?
A story is a sequence of worksheets or dashboards, called story points , arranged in order to walk a viewer through an analysis narrative — step by step, like a slideshow built from live, interactive Tableau content. Each story point can be a different worksheet, a different dashboard, or t...
9. What are Measures and Dimensions in Tableau?
Measures are the numeric metrics or measurable quantities of the data, which can be analyzed 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 nu...
10. What are the different Tableau products?
Tableau is a suite of related products rather than a single application, each aimed at a different part of the analytics workflow. Product Purpose Tableau Desktop Author workbooks, build visualizations and dashboards. Tableau Server Self-hosted platform to publish, share, and govern workbooks. Ta...
11. Advantages of Tableau.
Visualize Data : Rather than having complex computations over an Excel sheet, Tableau provides beautiful insights, data blending, and dashboarding derived from the data. Create interactive visualizations : Tableau provides a drag-n-drop facility to quickly let the users interact with the data. Yo...
12. What is Tableau Public?
Tableau Public is a free version of Tableau intended for publishing visualizations that anyone on the internet can view, rather than for private or internal business data. Workbooks are saved directly to Tableau's public cloud gallery, not to a private server. Every workbook published to Tableau ...
13. What is Tableau Server?
Tableau Server is the self-hosted platform organizations install on their own infrastructure to publish, share, and govern Tableau workbooks at scale, without giving every viewer a full Desktop license. Authors publish workbooks from Tableau Desktop directly to Server, where they live inside proj...
14. What is a parameter in Tableau?
The parameters in Tableau are the workbook variables like a number, date, or calculated field that allows users to replace a constant value in a calculation, filter, or reference line. For example, you create a field that returns true if the sales are greater than 30,000 and false if otherwise. P...
15. What is Tableau Prep?
Tableau Prep is a visual, drag-and-drop tool for cleaning, reshaping, and combining data before it ever reaches a Tableau Desktop workbook, aimed at the "data wrangling" step of analytics. You build a flow : a visual pipeline of steps like cleaning, filtering, splitting fields, pivoting, aggregat...
16. What are filters in Tableau?
Filters restrict the data shown in a view, letting you narrow a worksheet down to only the rows relevant to the question you're asking, without changing the underlying data source. Filters can be applied to dimensions (e.g. only show Region = "West"), measures (e.g. only show Sales > 1000), or da...
17. What are the different types of filters in Tableau?
Tableau applies several distinct kinds of filters, and understanding the order they run in matters as much as knowing what each one does. Filter Type What it does Extract Filter Limits what data is pulled into an extract at all. Data Source Filter Applies to every worksheet using that data source...
18. What is a calculated field in Tableau?
A calculated field is a new field you define using a formula built from existing fields, constants, and Tableau's built-in functions — it lets you derive values the raw data source doesn't already contain. // Profit Ratio SUM([Profit]) / SUM([Sales]) // Custom category IF [Sales] > 1000 THE...
19. What is a Tableau extract?
An extract is a compressed, optimized snapshot of your data that Tableau stores using its own Hyper engine format ( .hyper files), instead of querying the original database live every time. Extracts can pull the full dataset or a filtered subset, and can even be aggregated to a higher grain to sh...
20. What is the difference between a live connection and an extract?
This choice determines whether Tableau talks directly to your source database on every interaction, or works off a locally stored snapshot. Live Connection Extract Every query hits the source database in real time. Queries run against a local Hyper snapshot. Data is always current, down to the se...
21. What are the Rows, Columns, and Marks shelves used for?
These three shelves are where the actual structure of a Tableau view is defined — everything else is refinement on top of what you place here. Rows shelf : fields placed here define what appears down the vertical axis (or as separate rows in a table). Columns shelf : fields placed here defi...
22. What is the Marks card used for?
The Marks card is the control panel that determines how the data points in a view are visually rendered, sitting right next to the Rows and Columns shelves. Mark type dropdown chooses the base shape: Automatic, Bar, Line, Area, Circle, Shape, Square, Text, Map, Pie, Gantt Bar, Density, or Polygon...
23. What is a dual-axis chart, and how do you create one?
A dual-axis chart overlays two measures on the same view, each with its own independent Y-axis, so you can compare two metrics with different scales side by side in one chart rather than two separate ones. Columns: [Order Date] (by month) Rows: SUM([Sales]) SUM([Profit]) -- drag onto the same Row...
24. What is data blending in Tableau?
Data blending combines data from two separate data sources into one view, at the level of the visualization itself, rather than at the query level like a join does. One data source is designated the primary , the other the secondary ; the primary's row-level data effectively drives the view. Tabl...
25. What is the difference between data blending and a join in Tableau?
Both let you combine two data sources, but they operate at different stages and with very different implications for how detailed your results can be. Join Data Blending Combines data at the row level , before aggregation. Combines data at the visualization level , after aggregating the secondary...
26. What are the types of joins supported in Tableau?
When connecting multiple tables from the same data source, Tableau lets you join them using standard relational join types, configured visually in the data source pane. Inner Join Left Join Right Join Full Outer Join Only matching rows from both tables. All rows from the left table, matched rows ...
27. What is a context filter, and why would you use one?
A context filter is a filter you promote to run before all other (non-context) filters on the same worksheet, creating a temporary, filtered "context" that every other filter and calculation then operates within. Performance : if a worksheet has a filter that dramatically shrinks the data (e.g. R...
28. What is the order of operations for filters in Tableau?
Tableau applies different filter categories in a fixed order , regardless of the order you added them in the interface. Understanding this order explains many "why doesn't my filter work the way I expected" situations. Extract filters (if using an extract) — limit what's even pulled into th...
29. What are Sets in Tableau?
A set is a custom, reusable field that defines a subset of data based on a condition or a manually chosen list of members — effectively a saved "in/out" grouping you can drop onto a view. Fixed sets are built from a manually selected list of specific members (e.g. these 5 named customers). ...
30. What are Groups in Tableau?
A group combines several individual dimension members into a single, higher-level category, primarily to simplify a view or roll up related values without altering the source data. Group "California", "Oregon", "Washington" -> "West Coast" Group "New York", "New Jersey", "Connecticut" -> "Tri-Sta...
31. What is the difference between a Set and a Group in Tableau?
Both let you organize dimension members, but they answer different questions: a group asks "how should these members be relabeled/combined?" while a set asks "which members are in or out?" Group Set Combines multiple members into a new, renamed category. Defines an in/out membership condition (bi...
32. What is a hierarchy in Tableau?
A hierarchy arranges related dimensions in a parent-child order so viewers can drill down from a broad category to finer detail directly within a single view, using the small expand/collapse (+/-) icons Tableau adds automatically. Location Hierarchy: Country -> State -> City Tableau automatically...
33. What are table calculations in Tableau?
A table calculation is a calculation applied to the values already in a Tableau view, after the underlying query has returned and aggregated the data — as opposed to a regular calculated field, which is computed as part of the query itself. Common examples include running total , percent of...
34. What is the difference between a calculated field and a table calculation?
Both create derived values, but they operate at fundamentally different points in Tableau's query pipeline, which changes what each one can and can't do. Calculated Field Table Calculation Computed as part of the underlying query (row-level or aggregate). Computed after the query returns, on the ...
35. What is a Level of Detail (LOD) expression?
An LOD expression lets you compute an aggregation at a level of detail that's different from the granularity of the view itself — something neither a normal calculated field nor a table calculation can do on their own. { FIXED [ Cus t omer ID ] : SUM( [ Sales ] ) } { INCLUDE [ Order ID ] : ...
36. What is the difference between FIXED and INCLUDE LOD expressions?
Both add dimensions to control the level of detail, but they respond differently to whatever else you place on the view afterward. FIXED INCLUDE Ignores the view's own dimensions entirely; computes only at the fields listed. Adds its listed fields on top of whatever the view already has. Result s...
37. What is a Tableau action?
An action defines a piece of interactivity: clicking or hovering over a mark in one worksheet triggers a change somewhere else — another worksheet, a dashboard, or even an external URL — turning static charts into an interconnected experience. Filter Action Highlight Action URL Action...
38. What is the difference between discrete and continuous fields in Tableau?
Every field in Tableau is treated as either discrete (blue pill) or continuous (green pill), and this distinction drives how the field behaves on shelves, not just how it's colored. Discrete (Blue) Continuous (Green) Creates separate headers/categories on a shelf. Creates a continuous axis on a s...
39. What are the aggregate functions available in Tableau?
Aggregate functions collapse many row-level values into a single summarized value, and are the default behavior applied to every measure dropped onto a shelf. Function Purpose SUM Total of all values. AVG Arithmetic mean of all values. MEDIAN Middle value, less skewed by outliers than AVG. COUNT ...
40. What is the difference between a.twb and a.twbx file?
Both are Tableau workbook file formats, but they differ in whether the data itself travels along with the visual content. .twb .twbx Plain XML file describing worksheets, dashboards, and connections. A packaged ZIP-like archive bundling the .twb plus data extracts and local files. Requires access...
41. What is VizQL?
VizQL is the underlying query language and rendering engine that translates the drag-and-drop actions you perform in Tableau — dropping fields onto Rows, Columns, and the Marks card — into an actual database query, and then translates the query results into the visual you see. Every a...
42. How does Tableau handle NULL values?
Tableau treats NULL as "no value," and handles it differently depending on where it shows up: an axis, a dimension header, or inside a calculation. On a continuous axis (like a date or number line): Tableau shows an indicator icon in the bottom-right of the view noting that some marks are not sho...
43. What is a Gantt chart, and when would you use one in Tableau?
A Gantt chart plots bars along a timeline to show the duration and sequence of discrete tasks or events, making it the natural choice whenever "how long did this take, and when" is the question. Columns: [Start Date] (continuous) Rows: [Task Name] Marks: Gantt Bar, Size = [Duration] The Gantt Bar...
44. What is a heat map in Tableau?
A heat map encodes a measure's value using color intensity across a grid of two dimensions, letting you spot patterns, hotspots, and outliers at a glance across a large number of categories without reading individual numbers. Rows: [Sub-Category] Columns: [Region] Marks: Square, Color = SUM([Sale...
45. What is a treemap in Tableau?
A treemap shows hierarchical, part-to-whole data as a set of nested rectangles, where each rectangle's area represents a measure's magnitude and rectangles can be colored by a second measure or dimension. Marks: Square/Treemap type Size: SUM([Sales]) Color: SUM([Profit]) Label: [Sub-Category] Lar...
46. What is forecasting in Tableau?
Tableau's built-in forecasting feature projects future values for a time-series measure using exponential smoothing models, without requiring the user to write any statistical code. Analytics pane -> drag "Forecast" onto the view -> Tableau extends the line/bars with projected future values -> sh...
47. What are reference lines and reference bands in Tableau?
Reference lines and reference bands add a fixed benchmark directly onto a chart, so viewers can immediately see how actual values compare to a target, average, or acceptable range without doing mental math. Right-click the axis -> Add Reference Line -> Value: Average of SUM(Sales) -> Label: show ...
48. What is a bin in Tableau, and how is it different from a histogram?
A bin is a field that groups a continuous measure into fixed-size ranges (buckets), turning something like exact ages into ranges such as 0–10, 10–20, 20–30, and so on. Right-click [Age] -> Create -> Bins... -> Bin size: 10 -> produces a new field "Age (bin)" with values like 0,...
49. What is row-level security in Tableau?
Row-level security (RLS) restricts which rows of data an individual user can see in a published view, so the same dashboard shows different data to different people based on who's logged in — without needing to build a separate workbook per user or team. User-filter approach: { FIXED : IF U...
50. What is the difference between Tableau Desktop and Tableau Reader?
Both are desktop applications, but only one of them can actually build content — the other exists purely so people without a full license can still view work someone else created. Tableau Desktop Tableau Reader Licensed, paid product for authoring workbooks. Free product for viewing package...
51. What is a custom SQL connection in Tableau?
A custom SQL connection lets you write your own SQL query as the data source, instead of connecting to a table (or set of joined tables) through Tableau's visual data source pane. SELECT customer_id, region, SUM (sales) AS total_sales FROM orders WHERE order_date >= '2025-01-01' GROUP BY customer...
52. What is the Tableau Hyper engine?
Hyper is Tableau's in-memory, columnar data engine that powers extracts, replacing the older .tde format with a faster, more scalable architecture. Columnar storage lets analytical queries scan only the columns actually needed, rather than reading whole rows, which is a major speed advantage for ...
