Get rowcount of same ID's as new column

[ho86]

I'm a M newbie, having difficulties to create a new column (Table.AddColumn) with PowerQuery comprising the number of (count) of same values in the respective table. Any ideas how to accomplish this?

In the following example, I want to create a column based on the rowcount of transaction ID's

Transaction ID	Value	Rowcount (Unique Transaction ID)
1234	Hello	2
1234	This is	2
4567	A test	1

[ho86]

Thanks Pete, so much easier than I thought!

[BA_Pete · Accepted solution]

Hi @ho86 ,

You want to use the Group By function.

Select your [Transaction ID] column, go to Home tab > Group By.

In the dialog, create one aggregate column that has the 'Count Rows' operation, and one with the 'All Rows' operation.

Once your table has been grouped, you can expand your 'All Rows' column back out again to get your original columns back.

Pete