OK SQL/saved search gurus....here is a conundrum that has always been a puzzle for me.  I am trying to write a search that brings back all customers that have not placed any sales orders.  Some may have some other type of transaction but many simply have 0 transactions, ever.  Assuming that there is no data field on the customer record that references sales history (such as Last Sales Activity, which is not being used in this NS instance)....how do I do this with a search?  Seems that any join to transactions (sales orders or otherwise) will only produce rows that