Table.TransformColumnTypes

Table

Transforms the types of the specified columns in a table.

Syntax

Table.TransformColumnTypes(table as table, typeTransformations as list, optional culture as nullable text) as table

Parameters

Name	Type	Required	Description
`table`	`table`	Yes	The input table whose column types are to be transformed.
`typeTransformations`	`list`	Yes	A list of column name and type pairs, each specified as {columnName, newType}.
`culture`	`text`	No	Optional culture string used for locale-sensitive type conversions (e.g., "en-US").

Return Value

table — The input table with the specified columns converted to the given types.

Remarks

Table.TransformColumnTypes changes the data type of one or more columns. The typeTransformations parameter is a list of lists, where each inner list contains the column name and the target type (e.g., {{"OrderID", type text}}).

If a value cannot be converted to the target type, it results in an error for that cell. Use the optional culture parameter to control locale-specific formatting during conversion.

If you have multiple "Changed Type" steps in your query, consolidate them into a single Table.TransformColumnTypes call. Multiple separate type-change steps add unnecessary overhead and make the query harder to maintain.

When working with a database source (SQL Server, Oracle, etc.), be aware that Table.TransformColumnTypes can break query folding. If the type change happens after a foldable step, the engine may pull all data locally before applying the conversion. In database scenarios, prefer handling type conversions in the source query or use Table.TransformColumns with a conversion function instead.

Examples

Example 1: Change a single column type

Table.TransformColumnTypes(Sales, {{"OrderID", type text}})

Result

	OrderID	CustomerName	Product	Category	UnitPrice	Quantity	OrderDate	Region
1	1	Alice	Widget A	Widgets	25	4	1/15/2024	East
2	2	Bob	Gadget B	Gadgets	50	2	1/18/2024	West
3	3	Charlie	Widget C	Widgets	15	10	2/1/2024	East
4	4	Alice	Gadget D	Gadgets	75	1	2/10/2024	North
5	5	Diana	Widget A	Widgets	25	6	3/5/2024	West

Example 2: Change multiple column types at once

Table.TransformColumnTypes(Sales, {{"UnitPrice", type text}, {"Quantity", type text}})