I have a list of names in a REF column. I wou...

[Jonathon]

I have a list of names in a REF column. I would like to limit my users to entering only one REF record per name. Therefore, I would like to apply a valid_if statement to the REF column to remove options for which a record already exists.

I am wracking my brain trying to get this to work… I have tried so many combinations of SELECT() and IN() that I’m sure I’m working in circles at this point.

Has anyone done this before that can give some insight?

[pravse]

Assuming the table is T and the Ref column is RefName and it references T2, then the values that already exist are T[RefName]

So what you want is T2[KeyColumn] - T[RefName]

which is the same as

SELECT(T2[KeyColumn], NOT(IN([KeyColumn], T[RefName])))

[Jonathon]

Cheers Praveen, working.