Dynamically Change Column Types in Power Query M

Sets column types from a lookup list, skipping any column name that isn't actually present.

Data TypesIntermediatetypesdynamicschema

Power Query M code

let
    Source = YourTable,
    ColumnTypes = {{"OrderID", Int64.Type}, {"OrderDate", type date}, {"Amount", type number}},
    ExistingTypes = List.Select(ColumnTypes, each List.Contains(Table.ColumnNames(Source), _{0})),
    ChangedType = Table.TransformColumnTypes(Source, ExistingTypes)
in
    ChangedType

Notes

Update the ColumnTypes list with your own column names and target types.

Requirements

A table whose columns should always end up with a known type, even if some are missing.

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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