Tableau Mock Interview: 20 Questions in 50 Minutes

Choose by the question: comparison of categories uses bar charts, trends over time use line charts, part to whole uses stacked bars or treemaps with few categories, relationships between two measures use scatter plots, distributions use histograms or box plots, and geography uses maps. Keep charts simple and avoid pie charts with many slices, 3D effects or dual axes that confuse readers.

Discrete fields (blue pills) contain distinct, separate values and create headers or labels in the view. Continuous fields (green pills) form an unbroken range and create axes. Both dimensions and measures can be either. For example, YEAR(Order Date) as discrete shows separate year headers, while continuous dates draw a single timeline axis. Choosing correctly changes how the chart looks and how filters behave.

A box plot shows the distribution of a measure: the median line, the box covering the 25th to 75th percentile, whiskers extending to the data within 1.5 times the interquartile range, and outliers as points. In Tableau you add it from the Analytics pane or Show Me. It is useful for comparing delivery time, salary or order value distributions across groups.

Device layouts let you design separate versions of a dashboard for desktop, tablet and phone within the same dashboard. You can add, remove and rearrange items for each device, and Tableau shows the right layout based on screen size. For Indian field sales teams who check dashboards on mobile, a phone layout with key KPIs stacked vertically is very useful.

LOD expressions are computed in the data source as part of the query, so they can be used as dimensions, in filters and inside other calculations. Table calculations run on the aggregated results already in the view, so they depend on the view layout and addressing. LODs are better for fixed levels such as customer totals, while table calcs suit running totals, ranks and differences.

A URL action opens a web page, a file or an email link using field values from the selected mark. For example, clicking an order can open the order details page in an internal system with the Order ID passed in the URL, or clicking a company can open a search. URL actions can open in a new tab or inside a web page object in the dashboard.

Tableau Prep Builder is a visual tool for cleaning, combining and shaping data before analysis. A flow includes input, clean, aggregate, pivot, join, union and output steps, and shows data profiles to spot nulls and outliers. Output can be a hyper extract, CSV, or published data source. With Prep Conductor on Server or Cloud, flows can run on schedule as a repeatable pipeline.

Site roles define the maximum capabilities a user can have. Creator users can connect to data, build in Desktop and Prep and publish. Explorer users can explore and web edit existing data sources, with Explorer (can publish) allowing publishing. Viewer users can view and interact with dashboards. Site Administrator roles manage users and content. Permissions on content further restrict what each user can do.

Tableau uses exponential smoothing models to forecast continuous time series. It chooses the best model, with or without trend and seasonality, based on the data and shows prediction intervals. You need a continuous date and a measure. Options include forecast length, aggregation level and ignoring the last incomplete period. It suits quick projections, while complex forecasting needs Python or R integration.

Drag Customer Name to Rows and SUM(Sales) to Columns. Drag Customer Name to Filters, open the Top tab, choose By field, Top 10 by Sales Sum. For a flexible version, create an integer parameter and select it instead of the fixed 10, then show the parameter control. If other filters must apply first, add them to context so Top N works on filtered data.

Use relative metrics such as growth percent, sales per square foot or target achievement instead of absolute sales. Consider log scale for wide ranges, separate small multiples by store size band, or independent axes. Sorting and highlighting outliers also help. Explain the chosen normalisation in the subtitle so readers understand the comparison.

Create a date parameter with dynamic current value from a calculation such as MAX([Order Date]) or TODAY()-1, refreshing when the workbook opens. Filter the data with a calculation [Order Date] = [Selected Date] set to True. Show the parameter control. Users get yesterday by default and can pick another date without editing the workbook.

Use Tableau's embedding API or the Tableau web component to embed views in the portal, with single sign-on such as SAML or connected apps for authentication so users do not log in twice. Ensure users have licences and correct permissions, apply row-level security, set the dashboard size to fit the portal, and use the API to pass filters or parameters from the page.

Check the background task and job history for the error message. Common causes are expired or changed database passwords, firewall or VPN issues, schema changes like renamed columns, timeout because the query is too large, or Backgrounder overload at peak time. Fix credentials, update the data source, optimise the query or move the schedule. Set up failure email notifications.

The dashboard probably uses Automatic or Range size, so objects reflow on different resolutions. Set a fixed size suitable for the audience, such as 1366 by 768 or 1200 by 900, or use Range carefully with tiled containers. Avoid floating objects that overlap. Create a device layout for phones if needed and test on common screen sizes before sharing.

Situation: a director needed weekly sales numbers for a board call in three hours. Task: deliver correct numbers fast. Action: I clarified the exact metrics, reused an existing certified data source, built a simple view first, validated totals with finance, then improved formatting. Result: the numbers were ready in two hours and matched finance, and I later added the view to our standard dashboard.

Situation: I published a dashboard where a percent of total used Table Across and gave wrong numbers after a layout change. Task: fix it and rebuild trust. Action: I informed the stakeholder immediately, corrected the calc with Specific Dimensions, added a validation sheet comparing totals, and re-shared. Result: the issue was fixed within an hour, and I now test calcs after every layout change.

Situation: in my internship I could not get a running total to restart each year. Task: solve it without wasting a day. Action: I reproduced it on sample data, checked documentation on addressing and partitioning, tried Specific Dimensions, and asked a senior with a clear description when still stuck. Result: I fixed it within an hour and wrote a note for the team.

Situation: my dashboard needed customer data that was spread across three systems. Task: get a reliable, single table. Action: I wrote clear requirements with grain, fields and refresh needs, shared sample SQL, and reviewed their view together, testing counts against source systems. Result: they built a curated table, my dashboard became simpler and faster, and we reused the table for two other reports.