Table.ExpandTableColumn

Table

Expands a column of nested tables into individual columns in the parent table.

Syntax

Table.ExpandTableColumn(table as table, column as text, columnNames as list, optional newColumnNames as nullable list) as table

Parameters

Name	Type	Required	Description
`table`	`table`	Yes	The input table containing a column of nested tables.
`column`	`text`	Yes	The name of the column containing nested tables to expand.
`columnNames`	`list`	Yes	A list of column names from the nested table to extract.
`newColumnNames`	`list`	No	Optional list of new names for the expanded columns. If omitted, the original nested column names are used.

Return Value

table — The input table with the specified nested table column expanded into separate columns.

Remarks

Table.ExpandTableColumn takes a column that contains nested tables (typically the result of Table.NestedJoin or Table.Group) and flattens selected columns from those nested tables into the parent table.

Use the optional newColumnNames parameter to rename the expanded columns in the same step, rather than adding a separate Table.RenameColumns call. This keeps your query concise and reduces unnecessary steps.

Only expand the columns you actually need. Expanding all columns from a nested table and then removing most of them wastes processing time.

Examples

Example 1: Expand columns from a join result

let
    Joined = Table.NestedJoin(
        Table.SelectColumns(Table.FirstN(Sales, 3), {"CustomerName", "Product"}),
        "CustomerName", Customers, "Name",
        "CustData", JoinKind.LeftOuter
    )
in
    Table.ExpandTableColumn(Joined, "CustData", {"City", "State"}, {"Customer City", "Customer State"})

Result

	CustomerName	Product	Customer City	Customer State
1	Alice	Widget A	New York	NY
2	Bob	Gadget B	Chicago	IL
3	Charlie	Widget C	Houston	TX

Compatibility

✓ Power BI Desktop✓ Power BI Service✓ Excel Desktop✓ Excel Online✓ Dataflows✓ Fabric Notebooks