It seems in order to use join u need to add calculated field as well.
So If i do this FILTER(CustInvoiceTrans,CustInvoiceTrans.InvoiceId = CustInvoiceJour.InvoiceId) i get no errors but what if the relation requires more fields, how to add this to the filter condition?
I need to write sth like this: FILTER(CustInvoiceTrans,CustInvoiceTrans.InvoiceId = CustInvoiceJour.InvoiceId AND CustInvoiceTrans.InvoiceDate= CustInvoiceJour.InvoiceDate) but the syntax is wrong.