Create list of blank fields

[reddwarf]

Hi,
See attached mock-up.
I have a database style list that contain blanks in some fields
I wish to extract the ID and the field name (top row of list) to create a list of those blanks by ID, e.g.

ID Field
1 Field 3
1 Field 5
3 Field 2
3 Field 7

My list is over 1000 rows long and I just want to be able to quickly identify the blanks by ID

Thanks