Dropdown from 2 different tables

I have a column in table C where I would to insert a dropdown that takes the values from the key column of table A and the values from the key column of table B.

How could I proceed?

Regards

I have tried with SELECT(LIST(xxx), LIST(yyyy)) but not works

Untested, but maybe try the following to see if it works:

SELECT(TableA[KeyColumn], TRUE) + SELECT(TableB[KeyColumn], TRUE)

Hello, thanks for your reply.
With your code I have this error: “SELECT has invalid inputs”

The situation is this:
I have the form to create an event record:

  • Event record type X requires Key Column from Table A or Key Column from Table B (it works good)
  • Event record type Y requires:
    Column C (with a list of Key Column from Table A and Key Column from Table B) → my problem
    or Column D (with a list of Key Column from Table A and Key Column from Table B) → my problem

Try just one or the other first, to see if the SELECT statement still gives you an error still? I am guessing that you altered my suggested formula to match your actual columns?

The situation is this:
I have the form to create an event record:

  • Event record type X requires Key Column from Table A or Key Column from Table B (it works good)
  • Event record type Y requires:
    Column C (with a list of Key Column from Table A and Key Column from Table B) → my problem
    or Column D (with a list of Key Column from Table A and Key Column from Table B) → my problem

What Type of Column is [CF Dipendenti]? Is that list column of other relationships? SELECT() is finicky with listing a column like that, even if that column is a list of Key Columns. This will seem redundant, but try:

SELECT([CF Dipendenti][KeyColumn], TRUE)

I have the same error.

[CF Dipendenti] is the Ref column that takes the values from key column of table A (CODICE FISCALE)

I would create 2 field that takes:
List of the values of key column (CODICE FISCALE) from Table A
and List of the values of key column (CODICE FISCALE COLLABORATORE) from Table B

I have tried also with SORT() function, but not works

I thought I had provided another response late on Friday, but for some reason I’ve been getting a lot of “Sorry, unable to complete the action you requested.” error through this forum.

I think somehow by using [CF Dipendenti] it might be creating a circular reference, and therefore you are getting the error. Try one additional item just to see if it works in regards to the SELECT() statement:

SELECT(CODICE FISCALE[KeyColumn], TRUE)

I have solve joining in spredasheet the two tables DIPENDENTI and COLLABORATORE

What was the solution?

Joining the two table I could set in the dropdown field both ref DIPENDENTI and COLLABORATORE Keys

Now I am trying select in this field for each, mutiple fields.
It is possible?