Combine All CSV Files in a Folder in Power Query M

Reads every .csv file in a folder and stacks them into one combined table.

File HandlingIntermediatefoldercsvcombine files

Power Query M code

let
    Source = Folder.Files("C:\Data\CsvFiles"),
    FilteredCsvFiles = Table.SelectRows(Source, each [Extension] = ".csv"),
    AddedData = Table.AddColumn(FilteredCsvFiles, "Data", each Csv.Document([Content], [Delimiter = ",", Encoding = 65001, QuoteStyle = QuoteStyle.None])),
    Combined = Table.Combine(AddedData[Data]),
    PromotedHeaders = Table.PromoteHeaders(Combined, [PromoteAllScalars = true])
in
    PromotedHeaders

Convert CSV to JSON

Notes

All files must share the same column layout; adjust the delimiter/encoding if your CSVs use different settings.

Requirements

A folder containing CSV files with a consistent layout.

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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