Recently, I interviewed a few people for Power BI roles and here are some questions I asked in the initial rounds to assess their skill level. I’ve included sample answers below so you know how to approach such questions.
Prefer video? See this...
I made a video with 10 questions and my (elaborate) answers to them. Watch to learn how to answer such interview questions. See it below or on my YouTube channel.
1. What are the main differences between Power BI Desktop and Power BI Service?
Answer cues:
- Power BI Desktop is the main tool for creating or authoring reports.
- We use PBI desktop to clean up data, create data model, set up measures, build and refine charts and construct the reports.
- We then use Power BI Service to share the reports with the audience.
- Desktop = creation tool, Service = consumption tool
2. Explain the difference between a measure and a calculated column?
- Measures:
- calculate things on top of tables.
- calculated in the run-time based on the evaluation context.
- are usually aggregates.
- example: Shipment Count = COUNTROWS(Shipments)
- Calculated columns:
- are part of the table.
- are calculated at the time of creation based on the row-context.
- have one value per row.
- example: Discount Rate Row-wise calculation of discount rate based on order quantity
- Both measures and calculated columns use the same DAX language.
3. Describe the steps you would take to connect multiple data sources in a Power BI report?
- We can use Power Query to connect more than one source of data.
- We can also use PQ to merge / append / combine the data as needed.
- We can selectively load the data to Power BI and keep the rest in PQ level but customizing the load behaviour.
4. What do 1, * and arrow (â–¶) mean in the data model diagram?
- In a typical star-schema, we will have one to many relationship between dimension and fact table.
- The one side is denoted with a 1 and many side is denoted with a *
- The arrow indicates the direction of filter propagation.
- Power BI allows us to customize the filter direction (uni or bi-directional) and also have many-to-many relationships.
5. What is DAX and give me an example of DAX you've recently used?
- DAX stands for Data Analysis eXpressions. It is the main language of Power Pivot.
- Give examples based on your experiences and tell why / how they helped you solve problems.
6. How do you optimize the performance of a slow Power BI report?
- Answer questions like this based on your experience. If you have never optimized something, be honest and say that. Then give theoretical answers.Â
- Key optimization startegies:
- Reducing the data (filtering at PQ, Source level)
- Removing unwanted visuals, interactions and bookmarks
- Using performance profiler (Optimize ribbon in Power BI) to measure the performance of a page and identifying the problem areas.
- Setting up aggregate tables, pre-calculated views.
- [NEW] Using visual calculations instead of measures.
- Upgrading the Power BI on-prem servers, database servers (for direct query)
- Running time-consuming operations (such as PQ transformations) at low usage times (midnights, evenings)
7. How do you publish a Power BI Report to the service?
- Save and test the report. Make sure all calculations are correct and visuals represent the truth.
- Test any connections, refresh processes too.
- Publish the report (Publish button) and set the correct workspace.
- Test the report on the service view and make sure right people have access to the report.
- Optional, Send an email or share the report with the audience.
8. Explain RLS (Row Level Security) in Power BI?
- Row Level Security allows us to provide access to the relevant data to right people.
- For example, we can use RLS to show only USA data to the USA regional manager.
- We can use “roles” option in Power BI to set and test the roles.Â
9. What is a Slowly Changing Dimension (SCD) and how do you handle it in Power BI?
- SCD (Slowly Changing Dimension) is a dimension (or aspect of a dimension) that changes slowly over time.
- Give examples from your industry or previous work.
- Example: In our product table, we have a feature called cocoa percentage. For certain products this is changed once in a while based on customer feedback. This is an example of SCD.
- We can either replace the old values with new ones or create effective date based records.Â
10. How would you handle missing data?
- We can use either Power Query or Power Pivot to handle missing values in our data.Â
- Power Query shows missing values in a column thru Column Quality feature. We can use this to identify and deal with missing values.
- The key strategies for dealing with missing data are:
- Removing missing values
- Going back to source and fixing the problem
- Replacing missing values with an approximation (imputation)
- Ignoring missing values
Need more help? Watch the video
I made a video with 10 questions and my (elaborate) answers to them. Watch to learn how to answer such interview questions. See it below or on my YouTube channel.
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The topics covered are,
- What is Power BI? How to use it?
- Power BI vs Power Query vs. Power Pivot
- Understanding Power BI Visual interactions & customizing them
- Data cleanup and transformations with PQ
- Setting up a star schema data model
- Creating and using DAX measures
- Interactive storytelling in Power BI
- Saving & publishing your work
- Resources to learn more
- Q&A with you
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23 Responses to “Displaying Text Values in Pivot Tables without VBA”
Its possible to display up to 4 text values.
Have a look at the screen shot of an example that I had posted way back at the EHA and figure out how its done !
http://tinypic.com/r/muzywk/6
With Excel 2010 you can use Conditional Formatting to apply custom number formats which can display text. (In older versions you can only modify text color and cell background color, but not number formats.) Using CF allows for an even larger number of different display values.
[...] Display text values in Pivot Tables without VBA [...]
Hey,
Thanks, this helps. But how do you do it for multiple values where there is a huge amount of non repeating  text?Â
@Soumya
The only way to do more than 4 values is to make the Pivot Table manually with formulas, of course then it isn't a Pivot table
You can of course do it with VBA
You may want to have a look at this description of how to do it here: http://www.clearlyandsimply.com/clearly_and_simply/2011/06/emulate-excel-pivot-tables-with-texts-in-the-value-area-using-vba.html
@Soumya
The only way to do more than 4 values is to make the Pivot Table manually with formulas, of course then it isn’t a Pivot table
You can of course do it with VBA
You may want to have a look at this description of how to do it here: http://www.clearlyandsimply.com/clearly_and_simply/2011/06/emulate-excel-pivot-tables-with-texts-in-the-value-area-using-vba.html
[...] Pivot Tables take tables of data and allow the user to summarise and consolidate the data at the same time. This is a great and very fast method of analysis but is restricted to handling mathematical functions on the value field resulting in numerical summaries. – read more [...]
[…] Read more here:Â Displaying Text Values in Pivot Tables without VBA […]
There is a very good way actually for handling text inside values area.
First you create a special column on the very left side and call it ID, and put unique ID (numbers only), and then create a pivot table with:
Row Labels and Column labels as you like, and in the Values labels use the unique ID number.
Move the unique ID number (copy paste) somewhere to the right and use vlookup to load the data you need using the ID as reference.
It is a bit longer way but for me it works perfectly to combine values as you like in any moment.
hope helps.
Regards,
Jon
Thank you! I finally understand pivot tables thanks to your clear, concise explanations and examples.
Good Day. This is exactly what i have been looking for. However when i try it on my pivot table or even when i try to recreate this exercise using the sample worksheet, i get this error:
"Microsoft Excel cannot use the number format you typed. Try using one of the built-in number formats."
Same thing here, Excel quite did not like the format in my PowerPivot. Any clues as to what may be going on? Thanks.
I have the same thing happening on my end. I'm running a normal pivot table on a .xlsm file.
@Danzi
What format did you use?
can you post the file ?
pls. help in table there is name, pan. amount. i have to make pivot table for example
NAME PAN AMOUNT
MR.X AAAAC1254T 500.00
MR.Y AAABR1258C
MR.A CFVDE2458T
MR.Z AAVCR12548C
MR.X AAAAC1254T
MR.Z AADCD245T
pls. help in table there is name, pan. amount. i have to make pivot table for example
NAME PAN AMOUNT
MR.X AAAAC1254T 500.00
MR.Y AAABR1258C 1000
MR.A CFVDE2458T 2000
MR.Z AAVCR12548C 5451
MR.X AAAAC1254T 45564
MR.Z AADCD245T 4500
how to get pivot tabe so i get PAN no. against Name.
I found an easy way to get text values in pivot table.
I create an other worksheet in wich each cell has a formula that copy the pivot table. The trick is that the formula does a lookup for the numbers in the pivot table.
The formula looks like that:
=IF(ISNUMBER(table!A1);VLOOKUP(table!A1;Code!$A$1:$B$65;2);IF(ISBLANK(table!A1);" ";table!A1))
Code is a worksheet where there is a liste of text /numbers correspondance.
As a bonus The new sheet is easier to format
Additional trick:
In my case, i encoded differents codeid with a power(2, codeId-1) so that summing then is equivalent to concatenate them.
1-A
2-B
4-C
8-D
yields :
5 - AC
14 - BCD
Hi
I want to ask if pivot can display dates in pivot field. As in a column i have customers and in row different items i want to know there last purchase date. anyone help in this??
Hello Guys, Need your help
I am doing some analysis of the cycle time of the product i.e how much time a product takes from manufacturing to the central warehouse.
I have batch numbers for the product and against them i have to pull out the diff. dates
Like the base date is from where the manufacturing start. So i have the batch number,against it's manuf. date. Now i have to pull out the date when it was quality released.
I have the quality released data but the data have duplicates, like i will have two dates or may be three for the same batch. So my main objective is to pull out the date which is latest among them.
BATCH NO. DATE of Mfg. DATE of Quality release
A1 12/4/2014 (HERE I HAVE TO PULL value)
Next Sheet
BATCH NO. DATE of Quality Release
A1 14/5/2014
a2 23/5/2016
A1 12/5/2014
A1 13/6/2014
From this sheet i have to pull up the latest date format of date here is dd/mm/yyy
TIA
[…] needed to present text instead of counts in a pivot table value column. Here is an excellent resource for Excel manipulation, in addition to an overview of pivot […]
This is great thank you.
Wow!!! Excellent!! It helped me a lot.
I am developing training tracking sheet for 200 employees with training completed date. Each employee will be attending 25 courses. How to indicate actual dates in pivot table value field.