Table.ColumnNames Function in Power Query M (4 Easy Examples)

If you want to pull the list of column headers out of a table in Power Query, Table.ColumnNames is the function for that. It hands you every column name as a list of text, which you can then count, search, or pick from.

Table of Contents

Syntax of Table.ColumnNames Function

Table.ColumnNames(table as table) as list

where

table (required, table). The table whose column names you want to read.

Returns: a list of text, one entry per column, in left-to-right column order.

In plain terms, you give it a table and it gives you back the header row as a list.

Example 1: Get the list of column names

You have an Employees table and you want its headers as a list.

Here is the starting data:

EmployeeID	FullName	Department	Salary
E-101	Priya Nair	Finance	72000
E-102	Marcus Reed	Operations	68000

Pass the table straight to Table.ColumnNames:

let
    Source = Excel.CurrentWorkbook(){[Name="Employees"]}[Content],
    Names = Table.ColumnNames(Source)
in
    Names

Result: {"EmployeeID", "FullName", "Department", "Salary"}

The output is a list, not a table. The names come back in the same left-to-right order as the columns.

Example 2: Count the columns

Wrap the result in List.Count to find out how many columns a table has.

Here is the starting data:

OrderID	Customer	Amount	Status	Region
O-5001	Hannah Brooks	240	Shipped	West
O-5002	Rohan Gupta	980	Pending	South

Count the names that come back:

let
    Source = Excel.CurrentWorkbook(){[Name="Orders"]}[Content],
    ColumnCount = List.Count(Table.ColumnNames(Source))
in
    ColumnCount

Result: 5

This is how you count columns in Power Query, since there is no Table.ColumnCount function to do it for you.

Example 3: Check whether a column exists

Combine it with List.Contains to test for a column before you reference it.

Here is the starting data:

ContactID	Name	Phone	City
C-31	Derek Olson	555-2048	Denver
C-32	Ananya Iyer	555-7741	Seattle

Ask whether an Email column is present:

let
    Source = Excel.CurrentWorkbook(){[Name="Contacts"]}[Content],
    HasEmail = List.Contains(Table.ColumnNames(Source),"Email")
in
    HasEmail

Result: false

There is no Email column, so it returns false. This guards a step that would otherwise error on a missing column.

Example 4: Get the first column name by index

Since the output is a list, you can grab a single name with positional indexing.

Here is the starting data:

SKU	ProductName	Price
SKU-900	Wireless Mouse	18.5
SKU-901	USB-C Cable	9.0

Take the item at position 0:

let
    Source = Excel.CurrentWorkbook(){[Name="Products"]}[Content],
    FirstName = Table.ColumnNames(Source){0}
in
    FirstName

Result: SKU

Power Query lists are zero-based, so {0} is the first column and {1} is the second.

Things to keep in mind with Table.ColumnNames

The output is a list of text, not a table. To load it as a single column you have to convert it first, for example with Table.FromList.
It reads headers, not values. For the data in a column as a list, index the table directly with Source[ColumnName] or use Table.ToList.
Names come back in column order, left to right. Reorder the columns upstream and the list order changes with them.
Indexing past the end throws. Table.ColumnNames(Source){9} on a smaller table gives Expression.Error: There weren't enough elements in the enumeration to complete the operation. Use {9}? to get null instead.
Comparisons against the names are case-sensitive. List.Contains(Table.ColumnNames(Source),"email") returns false when the real header is Email.

Common questions about Table.ColumnNames

How do I get the column names of just some columns?

Table.ColumnNames always returns every column. To narrow it, filter the resulting list, or use Table.SelectColumns to keep a chosen set of columns and then read their names.

What is the difference between Table.ColumnNames and Record.FieldNames?

Table.ColumnNames reads the headers of a whole table, while Record.FieldNames reads the field names of a single record. Both return a list of text.

List of All Power Query Functions

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