5 Best Practices in Power Query

Summary

In this video, the speaker shares five essential best practices for improving Power Query queries. These tips focus on making queries more robust and readable by clearly naming steps, using comments to explain complex transformations, minimizing hard-coded values, parameterizing and staging queries, and utilizing the Quick Access Toolbar for efficiency. By following these practices, users can streamline their workflow, reduce errors, and create more maintainable queries in Power Query. Whether you're a beginner or experienced user, these insights will help you build professional and efficient data solutions.

Takeaways

• 😀 Naming steps clearly in Power Query makes transformations more understandable and easier to follow.
• 😀 Using descriptive names for each step helps you and others easily understand what transformations have been applied.
• 😀 Writing comments for complex transformations adds clarity, especially when certain actions cannot be fully described in step names.
• 😀 Commenting in Power Query can be done in the UI or M code to explain specific conditions or assumptions made during transformations.
• 😀 Minimizing hard-coded values (red signs) in your M code reduces the risk of errors if source data changes.
• 😀 Dynamic expressions can be used to fetch column names from previous steps instead of hard-coding them.
• 😀 Parameters make queries more flexible by allowing reusable values, such as file paths, that can be easily adjusted without modifying the entire query.
• 😀 Staging queries help prepare data in intermediate steps, enabling reuse and simplifying complex queries.
• 😀 Using parameterized queries helps avoid repeating the same work in multiple steps, streamlining the entire process.
• 😀 The Quick Access Toolbar in Power Query can be customized with frequently used tools to save time and increase efficiency in your workflow.
• 😀 Adding commonly used actions like the Advanced Editor or Custom Column to the Quick Access Toolbar allows you to quickly access these tools with shortcut keys, speeding up the query creation process.

Q & A

Why is renaming steps in Power Query important?

Renaming steps in Power Query is essential because it helps make your transformations clear and understandable. Instead of using generic names like 'Custom1' or 'Custom2', descriptive names like 'Keep all the files with the year label' make it easier to comprehend the transformations when revisiting or sharing queries.

How can I rename a step in Power Query?

To rename a step in Power Query, click on the step, press the F2 key, or right-click and select 'Rename'. You can then type the new descriptive name for the step.

What should I do if a transformation step is too complex to explain with a step name?

If a transformation step is too complex to explain in the name, you should add comments. Right-click the step, go to 'Properties', and write a description that explains what’s happening in the step. This helps provide clarity on complex transformations.

How do I add a comment to a step in Power Query?

To add a comment to a step in Power Query, right-click the step, select 'Properties', and type your comment in the description field. The comment will be visible as a small marker on the step, and hovering over it will display the description.

What does the red color in Power Query indicate?

In Power Query, red usually indicates hard-coded values, such as column names, paths, or parameters within the M code. These are prone to breaking when the source data changes, so it's best to minimize them to make your queries more robust.

How can I reduce hard-coded values in Power Query?

To reduce hard-coded values in Power Query, you can use dynamic referencing, such as `Table.ColumnNames`, to fetch values from previous steps instead of hardcoding them into the query. This helps ensure that the query remains functional even when data changes.

What is parameterization in Power Query and why is it useful?

Parameterization involves using parameters to store values like file paths or specific settings that can be reused across multiple steps or queries. It makes your queries more flexible, and you can easily update a parameter value without needing to change multiple steps in the query.

How can I create a parameter in Power Query?

To create a parameter in Power Query, go to the Home tab, click on 'Manage Parameters', and select 'New Parameter'. After defining the parameter (e.g., a file path), you can reference it in your queries to reuse the value across steps.

What is query staging, and how does it improve my Power Query workflow?

Query staging involves organizing your queries into distinct steps that can be reused by other queries. It helps optimize your workflow by allowing you to collect data once and use it across multiple queries, reducing redundancy and improving query performance.

How can I speed up my work in Power Query?

To speed up your work in Power Query, you can customize the Quick Access Toolbar to add frequently used actions like 'Advanced Editor' and 'Custom Column'. This allows you to quickly access these features using keyboard shortcuts (e.g., ALT + 1 for the Advanced Editor).