Query folding

Concept

Power Query optimization that pushes supported transformation steps back to the data source, such as a database, instead of evaluating them in the Power Query engine. Flat files like CSV and Excel cannot fold.

Title graphic: Query folding (Concept)

Type	Concept
Documentation	learn.microsoft.com/en-us/power-query/query-folding-basics

Key points about Query folding

The real execution order is the invisible engine plus query folding, not what the pane shows. · Power Query Folding and Execution Order in…

Episodes about Query folding

Power Query Folding and Execution Order in Power BI

2025-11-05 · Video on YouTube

Power BI is lying to you. Those neat, orderly “Applied Steps” you trust are a façade. Power Query is secretly rearranging, deferring, collapsing and sometimes ignoring the way you wrote your transform steps — which is why your filters don’t filter, your…

Power Query - Simply Explained

2026-10-29 · Video on YouTube

If you clean the same spreadsheet by hand every month, Power Query can turn that ritual into a process that repeats itself. This beginner-friendly episode explains the four phases, applied steps, the M language, merge versus append and the habits that keep…

Timeline of episodes about Query folding

Articles about Query folding (2)

Mastering Query Folding in Power BI: Push the Work to Your Data Source
2026-08-28 · Mirko Peters
When working with Power BI, few things are more frustrating than watching your data refresh take an eternity, or worse, watching it fail outright because it ran out…
Mastering Plain-English Queries with Microsoft Copilot Studio
2026-08-28 · Mirko Peters
Welcome back, data enthusiasts! Today, we are diving deep into a topic that is fundamentally transforming how organizations interact with their data stacks. If you …

Frequently asked questions

What is query folding in Power BI?

It is when Power Query translates steps into a source query that runs at the data source. The episode says it, together with the hidden engine, defines the true execution order of your transforms. · From the episode: Power Query Folding and Execution Order in…

Why did my refresh go from 20 seconds to 10 minutes?

Changes in how steps execute, such as losing query folding, can make a refresh dramatically slower. The episode says understanding the real execution order helps you find the cause instead of being blindsided. · From the episode: Power Query Folding and Execution Order in…

Are Applied Steps the real order of operations?

No. The episode calls them a façade over a hidden engine that rearranges, defers and sometimes ignores your steps. What actually runs is determined by the engine and by query folding. · From the episode: Power Query Folding and Execution Order in…

Glossary

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Sources

Documentation: learn.microsoft.com/en-us/power-query/query-folding-basics
Feed for this topic (RSS): entity/query-folding/feed.xml
M365.FM episodes on this topic: 2
Articles on this topic: 2

Maintained by Mirko Peters (Microsoft MVP) · Last updated: 2026-11-03