Remove Unused Columns Early in Power Query M

Drops columns you don't need as the very first step, so later transformations run on a smaller table.

Performance OptimizationBeginnerperformancecolumnsoptimize

Power Query M code

let
    Source = YourTable,
    RemovedOtherColumns = Table.SelectColumns(Source, {"OrderID", "OrderDate", "Amount"})
in
    RemovedOtherColumns

Notes

List only the columns you actually need for the rest of the query.

Requirements

A source table with more columns than you actually need.

How to use this snippet

In Power BI Desktop, choose Transform data to open Power Query, then open the Advanced Editor on a query (or start from a blank query).
Paste the snippet and replace the placeholder names (tables, columns, file paths) with your own. Check the requirements above first.
Run it through the Power Query M Formatter to tidy the layout.

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