Delete Data if Not Existing in Joined Table

hello guys, i need help here

I need to delete the Data in the Table if it's InventTransOrigin does not Exist in the Joined Table,

please see picture:

i only know how to delete existing data (this is my code):

while select forUpdate InventTransferLine
join inventTransOrigin
where InventTransferLine.InventTransID == inventTransOrigin.InventTransId
&& InventTransferLine.TransferId == InventTransferTable.TransferId

InventTransferLine.delete();

it deletes the existing data, but i need to delete the opposite, which is the not existing data.

please help modify this code, thanks.