Sequential numbering of Child Rows that restart with each parent row
I have a sheet with a parent row (PO number) and multiple child rows (parts ordered per PO number) that I am trying to auto-assign a number starting with 1, to the child rows of that parent only so I can use it to populate another sheet based on PO number AND that auto number. Is there a formula that can do that?
I've created a helper column [Item Number] that assigns a "1" to child rows and a "0" to the parent row. Then I have a second column [Item #] with the formula =SUM(PARENT([Item Number]@row):[Item Number]@row)) to assign 1,2,3,4,5,6... but I get an #UNPARSABLE error. If I use the formula =SUM($[Item Number]$1:[Item Number]@row)) IT works but doesn't start over after the next parent row. What am I missing?
Help Article Resources
Check out the Formula Handbook template!