Filtering A Lookup Column to Remove Duplicate Values


I’m trying to figure out how to filter a Lookup column so it only shows me results that aren’t in my table already.

What formula do I need to use to make that work?


  • I’m making a project tracker document and want to combine two tables into one so I can have a complete overview of all the info related to that project
  • I’m combining tables Project List and Invoice Info
  • I want the Project Name column to filter out any projects that are already in the table so I don’t get duplicate info

Here is a simplified version of the project: Project Tracker - Reference for Forum


Hi @Erin_P,
it’s not super clear to me why you would build a third table, once you already have all the information in the existing two (Project List and Invoice Info)

I’d rather use a view of Projects, being the “reference” table (every invoice will be connected to one project).

Have a look at this implementation:

Also, I see you’re preventing an invoice to be bound to any project. Do you want to have one single invoice per single project?
In that case the Lookup filter formula would be:
CurrentValue.Invoice.IsBlank() (also provided in my example).

I’m not sure about your use-case, so please let me know if I’m in the right direction.

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I originally made the Project List table include all the info from the Invoices table as well but found things were getting slow :woman_shrugging: Not sure why

Some projects have multiple invoices and I’ve been using a view of my Invoice table to create the invoices that I sent to clients. I’ve just been doing “Print to PDF” on the page to make a pdf from it

For future reference for other things though, is there a formula I can filter a Lookup column with that will make it so options that are already in the table are removed from the list?

Or is that just not a efficient way to approach things?

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