I have an edit gallery connected to a SharePoint list and there's an allowed values control where people are supposed to select a PO Number from a drop down in order to enter a comment. What I would like to do is to filter out any POs that already have comments associated with them in the SharePoint list named po_holds. Currently the Item property is set to po_holds.PO_Number. I'm trying to use filter but struggling with the syntax of how to make the items the PO_Number column while filtering on the Comments column. Something like:
Filter(po_holds.PO_Number, IsBlank(po_holds.Comments), but that doesn't work.
For an edit screen I would also like to use the converse of that filter.
