Quick Tip: Power Query column by example

It seems like everyone knows about how Power Query in Power BI Desktop lets you use web pages as data sources, and lets you build queries by entering values from the web page. This is probably because so many people use the “from web page by example” feature for demos[1].

It also seems like no one knows about the “column from examples” feature in Power Query, even though this is just as exciting, and much more useful. They’re both built on the same underlying intelligence, but this one lets you work with data from any source.

Here’s the quick overview:

  1. In the Power Query editor in Power BI Desktop, choose “Column from Examples” from the “Add Column” tab.
  2. Enter the values that the new column should have for rows that are already in your data set.
  3. Review the values that Power Query is suggesting for the other rows, and when they are all correct, choose OK, and then say “Ooooooohhhhh” when Power Query does all the work for you.

Like this[2]:

column by example

In this example, I want to extract an ID value from a URL column where the URLs all follow the same pattern. I’ve copied the ID value from the first row, and when I paste it in to the new column, Power Query immediately generates the M code to extract the ID and adds a new step the query.

= Table.AddColumn(#”Renamed Columns”, “Text After Delimiter”, each Text.AfterDelimiter([Band Page URL], “/”, 4), type text)

This code isn’t too complex. You could have written this code. I could have written it, but odds are it would have taken me a few minutes to look up the syntax for the Text.AfterDelimiter function, and to iterate a few times getting it right. Using this awesome feature I get the same code in seconds. For more complex scenarios you may need to enter more than one desired value before Power Query has enough information to get the function just right.

The best part is that the step that is added is just another query step. You can delete it, you can edit it, you can add more steps after it. This is just a fast and simple way to add the step without needing to write any code or even know what functions to use.

There have been a few occasions where Power Query couldn’t quite figure out what I needed it to do, but it hasn’t happened often, or lately. This may be because I’ve been getting better, but it’s probably because the Power Query team has continued to improve the feature since it was introduced in April 2017. That’s right – this feature has been available for over two years, and you’re just learning about it now.

Or are you[3]?

Either way, check it out the next time you’re working in Power Query, and let me know what you think.


[1] To be fair, it does make for an awesome demo.

[2] There also used to be a GIF here, but apparently my GIF-making skills need some refinement before I start using GIFs in blog posts.

[3] When I demo Power Query in Power BI Desktop to customers, maybe 10% have already seen this feature already. I suspect that the high quality demographic that this blog is certain to attract will be more aware and more engaged than the general population, so I’m genuinely curious to know if you already knew about this gem.

2 thoughts on “Quick Tip: Power Query column by example

  1. Pingback: Dataflows in Power BI – BI Polar

  2. Pingback: Column From Examples in Power Query – Curated SQL

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