Updating Parent part system to all child parts

[rippernash]

I have a table that is an extract from a Bill of Materials.

I have columns A (Identifier) and B (Parent Identifier) already calculated. Currently, under column D (Part System), only the cells against the main BOM Module has a part system. I want to update this Part System to all the cells that have a 0 (child parts) based on the value in column B (Parent Identifier). If a cell in D already has a value, it should not be updated.

(Figure 1: File before part system update)

(Figure 2: After Part system update)

I am looking for either a VBA macro or formula query to achieve this. The full file has thousands of rows so performance is important.

Thanks in advance!

 

[Peter_SSs]

Welcome to the MrExcel board!

Can you explain the logic of how those expected results are obtained. In words, give the steps of how to do 1 or 2 of them.

Also, helpers will not be inclined to do that large amount of typing to try things out. Consider the following:

MrExcel has a tool called “XL2BB” that lets you post samples of your data that will allow us to copy/paste it to our Excel spreadsheets, so we can work with the same copy of data that you are. Instructions on using this tool can be found here: XL2BB Add-in

Note that there is also a "Test Here” forum on this board. This is a place where you can test using this tool (or any other posting techniques that you want to test) before trying to use those tools in your actual posts.

 

[rippernash]

I apologize for the vagueness. Here is the logic: For every cell in range D2:D, look at corresponding cell in column B2:B. Then search for the first matching exact string in range of column A2:A, and if found, return the value of cell D2:D (or a copy of D2:D to avoid self reference).

 

[Peter_SSs]

For every cell in range D2:D, look at corresponding cell in column B2:B.

You don't really mean every cell in D onwards do you? Otherwise D5 in your sample would be "Vehicle Integration"
I assume that you mean every cell in D2 onwards that currently holds a 0?

Any chance we could have that sample data with XL2BB as mentioned in my previous post? A lot of typing to set that up to test (& would be very easy to make a mistake )