Retrieve header fields like response status from Web.Contents in Power BI and Power Query

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Many Power Query function not only return their values as advertised in their function documentation, but on top of that a metadata record. This record is like tag that holds additional information about the returned main value (for more details about this, please check out my friend Lars Schreiber’s article about it). Useful metadata for … Read more

Split up an existing Power BI report into a Golden Dataset and a thin report

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Edit 24thJune 2021: Unfortunately this method is currently not working any more.

The other day I discovered a neat way to split up an existing Power BI report into a Golden Dataset and a thin report file with very few adjustments to the existing setup. Imagine you have a Power BI report published for some time already in an app with row level security. Now, you want to create other reports from the dataset as well and decide it’s time to create a golden dataset from which multiple other thin reports can also be fed from as well. But ideally you want to keep your published app, that many users are working with already, unchanged.

Concept to split up existing Power BI Report to Golden Dataset

Simply follow these steps in meticulous order and the world is yours 🙂

Steps to split up existing Report to Golden Dataset

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Transform a query into a function in Power Query and Power BI

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In my previous blogpost I’ve described a method how to extract a substring that follows a certain pattern from a string. In this post I show how to transform a query into a function that can be applied to many rows of a table.

Video how to transform a query into a function

Please check the video for detailed steps. In there I also show how to modify the code. It shall also detect strings with a sequence of just 8 numbers. In the original query, those had to be followed by a minus sign and another number:

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Extract pattern string and numbers from text using List.Accumulate in Power Query

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A typical task when cleaning data is to extract substrings from string that follow a certain pattern. In this post I’m going to describe a method that uses the List.Accumulate function for it. Extract a pattern string.

Task

I have to extract a payroll key from a description field that starts with 8 number, followed by an “-” and another number.

aölsfdk0125-fds  da12345678-0asdf

So I’m after the 12345678-0.

Plan

I plan to approach this by

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Performance tip to speed up slow pivot operations in Power Query and Power BI

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Pivot operations in are a very handy feature in  Power Query but they can slow down refresh performance. So with some bittersweet pleasure I can tell that I found a trick to speed them up. The sweetness comes from the fact that the performance improvement is very significant. But the bitterness comes from the fact that I could have used this for almost 4 years now, but was too blind to realize at the time when I first worked with the code.

Trick to speed up a slow pivot table

This might not work everywhere, but for my tests, it worked really well: Don’t use an aggregation function when you want fast pivoting:

slow pivot
Don’t aggregate when you want a fast pivot in Power Query

But if your data isn’t aggregated on the row- & column values already, you’ll get this error message:

Error when the values are not adequately aggregated

So to make this work, you have to aggregate the values on the axis’ values before.

Let’s walk through the steps:

Walkthrough

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How not to miss the last page when paging with Power BI and Power Query

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paging pagination Power Query

When you use an API with a paging mechanism (like the example from this blogpost), you’ll might work with a field that contains the address for the next page. You can use this to walk through the available chunks until you reach the last element. That last element in the pagination will not contain a next-field or that field will be null.

Paging in Power Query

In Power Query you can use the function List.Generate for it. According the latest function documentation it:

Generates a list of values given four functions that generate the initial value initial, test against a condition condition, and if successful select the result and generate the next value next.

So an intuitive implementation would look like so:

paging pagination Power Query
Initial code for paging: Will miss the last element

In the initial step (row 2) the API will be called and returns this record:

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