Use SharePoint list validation or column validation on a choice column from the dropdown is selected once for a project

Question

Use SharePoint list validation or column validation from a choice from the dropdown is selected once I have a project detail page, which is a SharePoint list, this SharePoint list has a choice column Metric Type Status. We want to restrict users to only allow them to select an entry in the dropdown "In Progress" once.

We could perhaps do this by "Project Name" which is also another column in this SharePoint list, to ensure a Project has only one entry or row with the Metric Type Status is equal to "In Progress"

Here's some context: I have SharePoint Online. No access to SP designer. I'm guessing we can do this by writing a formula under list settings -> validation settings Or we can click list settings -> Metric type -> insert formula into column validation I really would want to avoid custom Javascript

Answer 1

You could achieve this through list validation.

Here are steps:

1.Go to List Settings.

2.Click "Validation Settings" under "General Settings".

3.Use this validation formula: =IF([Metric Type Status]="In Progress",TRUE,FALSE)