What is filtering during transformation vs extraction?

< 1 min read

Filtering during extraction means retrieving only required data from the source itself.
For example, SQL query pulls only last 12 months of sales instead of full table.
This reduces data volume, network load, and refresh time.
Filtering during transformation means applying conditions in Power Query after data is loaded.
For example, keeping only “Completed” orders from the full dataset.
It does not reduce source extraction but shapes data for analysis.
Extraction filtering improves performance; transformation filtering improves report relevance.
Both are used together for efficiency and clean datasets.

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