Filter a dropdown list based on its own list.

[7_Ideas_Digital]

Hi everyone:

I have a problem when I want to filter a dropdown with values already selected for a record. I have to record the attendance of the employees daily, so I select a day and add each employee.

Then I select the employee and it is added to the record for that day, however when I want to add another, the employee that I had already added continues to appear, making the list always show the same number of employees and not just those that have not yet been registered. For example: If I have 20 active employees, the list shows 20 the first time, when registering one I would expect that the next time I select from the dropdown only 19 will appear (those who have not yet registered).

Until now, I am only showing the list of all employees and I have not been able to leave out those that were already added.

Any idea or trick to solve this impasse?

I appreciate any suggestion. 

[graham_howe]

You can use List Subtraction | AppSheet Help Center to remove a list of employees who were already added. To get the list of employees already added just do another select. So your expression would end up being SELECT(all employees) - SELECT(already added employees). You should probably use a unique condition around the second select.

[7_Ideas_Digital]

Thank you Graham for the prompt response. That is exactly what I cannot write since the records that I am adding are not yet saved in the spreadsheet, the field is marked as "Is a part of?" so I can't do the subtraction during the add process, can I?

Any example you have would help me a lot.

Thank you.