One-to-Many Relationship with Null Value

Hello All,

I hope you are well!

I am looking to create a one-to-many link between two tables (Mastertable and Project_Table) based on a column entitled "Project Code."

Mastertable has the project code as well as other information on the project such as opportunity name, contact, lead source, type of project, etc. Mastertable does not contain any financial data.

Project_Table on the other hand only has three columns, the opportunity name, the project code and the opportunity amount.

My goal is to link the financial data to my Mastertable using a a one-to-many match based on the project code. However, not every opportunity is assigned a project code at the same time. So, my Project_Table has multiple null values under the project code column because of timing differences. As I try to create the link between tables, I am running into an error where the project_table "contains a duplicate value 'Null'." Is there a way to have the one-to-many link ignore rows with nulls in the project code column or do I need to clean the data better at the source?

Any tips/suggestions are welcome! Thanks in advance 🙂

P.S. data is confidential so I can't provide any datasets but can answer any questions if the two table setup isn't clear.