Error using expression SELECT to compile a list of Email-recipients

Hi there,

I’m building an app which can compile Emails to the participants of different meetings. I have the following tables in my data structure (among others):

  • Employees
  • Meeting Categories
  • Meetings

In my Meeting Categories I define the name of the meeting and which employees attend the meeting.
A Meeting is an instance of a meeting category. For example, a sale meeting (meeting category) is held every month (meeting).

I have built an action of the type ‘External: Start an Email’ for a record of the meeting table. In the ‘To’ field I have composed the expression

‘SELECT(Employee[Email],[Meeting Category]=[_Thisrow].[Meeting Category],TRUE)’

This should ensure that only the employees which are added to the meeting category of this meeting are getting an email. However, I get an error saying:

The expression is valid but its result type ‘List’ is not one of the expected types: Email

Can anyone help me with this? Is it impossible to compile a list in this field? Should I use another expression? Or is it possible to use an expression to change my LIST into a STRING, with a seperator ‘;’? This would solve this problem as well, as this is the separator Outlook uses.

Tx in advance!


You are right that in this situation Appsheet wants to take a text string and place it in the mail app’s to: line. Wrap your existing expression in concatenate([LIST],"; ") and that should do the job.

concantenate( SELECT(Employee[Email],[Meeting Category]=[_Thisrow].[Meeting Category]), "; ")

Correct! You would want to use a column type that allows lists.

I would recommend using a Virtual Column. They can accommodate Lists directly.

A Virtual Column is probably appropriate anyway since the list of meeting participants could change at anytime and you probably would want to re-calculate on the fly as needed rather than store the list in the datasource.