36 practice questions with answers for Power BI interviews in Nagpur.
Power BI jobs in Nagpur
Nagpur's MIHAN SEZ hosts IT-services and BFSI delivery centres, giving central India a steady market for data and QA roles. Interviews are usually service-company style, with aptitude, technical and HR rounds.
Below are 36 questions that match the mix of service, product and domain employers hiring power bi developers in Nagpur.
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01
What is conditional formatting and where can you apply it?
Conditional formatting changes colours, icons, data bars or font based on values or rules, helping users spot good and bad performance quickly. You can apply it to table and matrix cells, backgrounds, font colour, chart data colours and titles using field values, rules or a measure that returns a colour code. A measure returning hex colours gives full control, such as red when below target.
02
Scheduled refresh fails every night with a gateway error. How do you troubleshoot?
I would check the refresh history error details, confirm the gateway machine is on and the gateway service is running and updated, and verify data source credentials in the gateway connection have not expired. Then test connectivity from the gateway machine to the source and check that the source names in the model exactly match the gateway data source. Gateway logs and network or firewall changes are next.
In Table view or Model view, select the date table, choose Table tools, Mark as date table, and select the date column, which must be unique, contiguous and without blanks. This tells Power BI to use it for time intelligence and disables the auto date hierarchy for that table. Also turn off Auto date/time under Options, Data Load to avoid hidden date tables for every date column.
04
A slicer on Product Category does not filter the Targets visual. What do you check?
I would check the relationship path in model view: whether Targets is related to the Product or Category dimension at all, whether the relationship is active, and its cross-filter direction. If Targets are at category level, it needs a relationship to a Category table that also filters Product. Also check whether visual interactions were turned off for that slicer and whether the measure uses ALL or REMOVEFILTERS.
05
How do you build a toggle between a chart and a table using bookmarks?
Place a chart and a table in the same position. In the Selection pane hide the table and create a bookmark named Chart View with Data unchecked so filters are not saved; then show the table, hide the chart and create Table View. Add two buttons and set each button's action to the matching bookmark. Group the visuals to keep the layout tidy.
06
What modelling practices reduce Power BI model size?
Remove unused columns and rows, avoid high-cardinality columns like GUIDs and datetime with seconds by splitting date and time or rounding, use integer surrogate keys, prefer measures over calculated columns, turn off Auto date/time, and choose the right data types, such as fixed decimal. Load only the history users need, and summarise data where detail is not required.
07
Tell me about a time you found a wrong number in a published report.
Situation: a regional head noticed our margin report did not match finance. Task: find and fix it quickly. Action: I compared numbers at product level, found returns were double-subtracted because a measure used both a net amount column and a returns table. I fixed the measure, added a reconciliation page against finance totals and informed users. Result: numbers matched to the rupee and the reconciliation check became standard.
Power BI Free lets a user build in Desktop and use My workspace but not share content. Power BI Pro is needed to publish to shared workspaces and share with other Pro users. Premium Per User adds larger models, more refreshes and premium features per user. Fabric capacity (F SKUs) provides dedicated capacity; at F64 and above, viewers with a free licence can consume shared content.
09
What is the difference between Reference and Duplicate in Power Query?
Duplicate copies all the steps of a query into a new independent query, so later changes to the original do not affect it. Reference creates a new query whose source is the output of the original, so it inherits any changes. Reference is useful for building several tables from one staging query, such as dimension tables from a cleaned sales table, while Duplicate is for experimenting separately.
10
What is a calculated table and when would you use one?
A calculated table is created with a DAX expression and stored in the model, recalculated at refresh. Examples are a date table using CALENDAR, a disconnected parameter table for what-if analysis, or a summary table. It is handy but adds memory, and it cannot use Power Query folding. For most shaping tasks, creating tables in the source or Power Query is preferred.
11
How do you explain a technical limitation to a business user who wants something impossible?
I acknowledge the goal, explain the limitation in simple terms and offer an alternative that meets most of the need. For example, when a user wanted live updates every second on a DirectQuery report over a slow system, I explained the load it would create and offered a 15-minute refresh plus an alert for threshold breaches. They accepted because the key decision was covered.
12
A matrix with 200,000 rows makes the report slow and unusable. What would you suggest?
Large detail tables are rarely read on screen. I would understand the real need: if users want to search specific records, add slicers or a search filter and a drill-through page; if they need to export, provide a paginated report or analyse in Excel. On the main page I would show aggregated results with top N filters, which improves both speed and readability.
13
What is the relationship between Power BI and Microsoft Fabric?
Microsoft Fabric is Microsoft's unified analytics platform that includes data engineering, data factory, data warehousing, real-time analytics and Power BI as its reporting layer. Power BI workspaces can live on Fabric capacity and use items such as lakehouses and warehouses in OneLake. Direct Lake mode lets semantic models read Delta tables in OneLake directly without a full import, combining fresh data with near-import speed.
Cardinality describes how keys match between two tables. One-to-many is the normal type, from a dimension's unique key to a fact table's repeating key. One-to-one links tables with unique keys on both sides and often means they should be merged. Many-to-many allows duplicates on both sides; it is supported but can produce confusing totals, so a bridge table is often clearer.
15
Describe a time you cleaned very messy data under a deadline.
Situation: a client sent 36 monthly Excel files with merged headers and changing columns two days before a review. Task: build a consolidated sales report. Action: I used the Folder connector with a custom function that promoted the right header row, unpivoted month columns and mapped renamed fields through a lookup table. Result: the report was ready a day early, and future files loaded automatically with no manual work.
16
How does the VertiPaq engine store and compress data?
VertiPaq is the in-memory columnar engine for Import models. It stores each column separately and compresses it using dictionary encoding, which maps unique values to integers, value encoding for numbers, and run-length encoding for repeated sequences. Compression depends mostly on column cardinality, so columns with few unique values compress very well, while unique IDs and precise timestamps take most of the memory.
Best Practice Analyzer, in Tabular Editor and also available in Fabric notebooks through semantic link labs, scans a semantic model against a set of rules, such as avoiding bi-directional relationships, hiding foreign keys, not summarising numeric IDs, using DIVIDE, and setting format strings. It lists violations with their severity so teams can fix them before release. Rules can be customised to match team standards.
18
Your model has one wide flat table with 80 columns from an Excel export. How would you remodel it?
I would identify the grain, such as one row per order line, and split descriptive attributes into dimension tables like Customer, Product, Store and Date using Reference queries and Remove Duplicates on keys. The fact table keeps keys and numeric columns only. Then create one-to-many single-direction relationships. This reduces size, simplifies DAX and makes slicers faster and more reliable.
19
What is cross-filter direction and why is bi-directional filtering risky?
Cross-filter direction controls which way filters travel across a relationship. Single direction, from the one side to the many side, is the default and safest. Bi-directional lets the fact table filter the dimension too, which can be useful for slicers showing only relevant values, but it can cause ambiguous paths, unexpected results and slower queries. Prefer single direction and use CROSSFILTER inside specific measures when needed.
20
Rewrite a slow measure to use variables and avoid repeated calculation.
Before:
Growth = IF([Sales PY] = 0, BLANK(), ([Total Sales] - [Sales PY]) / [Sales PY])
After:
Growth =
VAR cur = [Total Sales]
VAR py = [Sales PY]
RETURN DIVIDE(cur - py, py)
The previous year measure is now evaluated once instead of three times, and DIVIDE handles zero safely.
A date table gives one row per day with columns like year, quarter, month, week and fiscal periods, so all facts can be analysed on a common calendar. Time intelligence functions such as TOTALYTD and SAMEPERIODLASTYEAR need a contiguous date column, and the table should be marked as a date table. It also avoids the many hidden auto date/time tables that bloat the model.
22
How do you explain a data model to a non-technical stakeholder?
I use a simple analogy: the fact table is the list of transactions, and dimensions are the labels we use to slice them, like date, product and region. I show the model diagram with only main tables and explain that slicers work through these links. Then I demonstrate one visual changing when a slicer changes, which makes the idea concrete quickly.
23
Write a measure for percentage of grand total sales.
Sales % of Total =
DIVIDE(
[Total Sales],
CALCULATE([Total Sales], REMOVEFILTERS('Product'))
)
This gives each product's share of total across all products. Use ALLSELECTED('Product') instead if the denominator should respect slicer selections on products.
24
What tools do you use to analyse Power BI performance?
Performance Analyzer in Desktop records how long each visual takes for DAX query, visual display and other work, and lets you copy the query. DAX Studio runs those queries with server timings and query plans and includes VertiPaq Analyzer for model size by table and column. Best Practice Analyzer in Tabular Editor flags modelling issues. In the Service, capacity metrics apps show load on Premium or Fabric capacity.
Create a new page, set Page information, Allow use as tooltip on, and set Canvas settings to the Tooltip size. Add small visuals like a monthly trend line for the hovered item. On the main visual, go to Format, Tooltips, set Type to Report page and select the tooltip page. Fields in the main visual automatically filter the tooltip page on hover.
26
How do you control how visuals interact with each other?
By default, selecting a data point cross-filters or cross-highlights other visuals on the page. Use Format, Edit interactions to choose filter, highlight or none for each visual pair, for example stopping a slicer from affecting a target KPI card. Slicers can also be synced across pages with the Sync slicers pane. Clear interaction design prevents confusing behaviour.
VAR defines a named value inside an expression and RETURN gives the final result. Variables make measures easier to read, avoid repeating the same calculation, which improves performance, and help debugging because you can return an intermediate variable. A variable is evaluated once in the context where it is defined, so its value does not change if later CALCULATE filters are applied.
28
What is a disconnected table and how is it used for what-if analysis?
A disconnected table has no relationship to the model and is used to capture a user's choice through a slicer. For example, a Discount table from 0 to 30 percent created with GENERATESERIES, or the What-if parameter feature, lets a measure read SELECTEDVALUE(Discount[Value]) and calculate projected revenue. Since it does not filter facts, the measure decides how the selection is applied.
Default tooltips show field values when hovering over a data point. Report page tooltips let you design a small custom page, set as a tooltip page type, showing extra visuals like a mini trend chart for the hovered category. They add detail without cluttering the main page. Keep tooltip pages light because they run queries on every hover.
30
How do you handle errors in Power Query without failing the whole refresh?
Use Keep Errors on a copy of the query to inspect the bad rows, then fix the cause, such as wrong data types or invalid dates. Replace Errors can substitute a value, and in M try ... otherwise catches errors per value:
= Table.AddColumn(Source, "AmountNum", each try Number.From([Amount]) otherwise null, type nullable number)
Log error rows to a separate query so they can be reviewed rather than silently dropped.
31
A report page takes 25 seconds to load. Walk me through how you would fix it.
I would run Performance Analyzer to find the slowest visuals, copy their DAX queries into DAX Studio and check server timings. Common fixes are rewriting measures that iterate large fact tables, removing bi-directional relationships, reducing visuals on the page, and shrinking the model by removing high-cardinality columns. If the source is DirectQuery, I would add aggregations or move to Import. Then re-measure after each change.
32
What are endorsement, sensitivity labels and lineage view?
Endorsement marks content as Promoted by its owners or Certified by authorised reviewers, guiding users to trusted semantic models. Sensitivity labels from Microsoft Purview classify content, such as Confidential, and labels flow to exports like Excel and PDF. Lineage view shows how data sources, dataflows, semantic models, reports and dashboards depend on each other, which helps impact analysis before changes.
33
Split a datetime column to reduce cardinality in Power Query.
= Table.AddColumn(Source, "OrderDateOnly", each DateTime.Date([OrderDateTime]), type date)
= Table.AddColumn(Prev, "OrderHour", each Time.Hour([OrderDateTime]), Int64.Type)
Then remove the original OrderDateTime column. A datetime with seconds can have millions of unique values, while date and hour columns have only thousands and 24 values, compressing much better.
34
What is the difference between Group By in Power Query and summarising in DAX?
Group By in Power Query aggregates rows at refresh time and stores only the summarised table, reducing model size, which is useful when detail is never needed. Summarising in DAX through measures keeps detail in the model and aggregates dynamically for any filter at query time. Use Power Query grouping for fixed summaries such as monthly snapshots, and DAX measures when users need flexible slicing.
35
A business user asks to merge customer and sales into one table to make it easier. How do you respond?
I would explain that a star schema with separate Customer and Sales tables is easier for them in practice: slicers are cleaner, totals are correct and reports run faster. To keep it user-friendly I would hide key columns, organise measures in display folders and name fields in plain language. I would show them the field list so they see simplicity on the surface.
Visual calculations are DAX calculations defined directly on a visual and computed on the visual's own aggregated data, rather than on the model. They make running totals, moving averages, percent of parent and comparison with previous rows simpler using functions like RUNNINGSUM, MOVINGAVERAGE and PREVIOUS. They do not add measures to the model, so they suit visual-specific logic but cannot be reused across visuals.
Few big employers listed in Nagpur?
Many Nagpur candidates also apply to teams in Pune and to remote or hybrid roles. Practise the Pune set as well.
Which companies hire Power BI professionals in Nagpur?
Companies with large offices in Nagpur include many IT services and product firms. Use their company pages below to practise employer-specific sets.
Are Power BI interviews in Nagpur different from other cities?
The questions depend more on the company than the city. Nagpur's mix of employers decides the style: Interviews are usually service-company style, with aptitude, technical and HR rounds
How do I find Power BI jobs in Nagpur?
Shortlist companies with Nagpur offices, keep your CV focused on Power BI projects, apply on company career pages and job portals with the Nagpur filter, and practise the questions on this page before each interview.