I like to google for new and better ways to do things.. so i stumbled over this post and...Well what worked good in SQL7 and works good in SQL2016 is to just use a outer join and look for NULL values(null is missing data) ....
insert into DestTable (keyCol1,col1,col2,col3...)
select keyCol1,col1,col2,col3,...)
from SouceTable as s
left outer join DestTable as d on d.KeyCol1=s.KeyCol1
where d.KeyCol1 is null
and ...
feel free to test it
wrap your statement in a transaction, delete a few rows and see them come back in the select statement that would normally insert the rows in the destination table...
BEGIN TRAN
--> delete a subset of the data, in this case 5 rows
set rowcount 5;
-->delete and show what is deleted
delete from DestTable;
OUTPUT deleted.*,'DELETD' as [Action]
--> Perform the select to see if the selected rows that are retured match the deleted rows
--insert into DestTable (keyCol1,col1,col2,col3...)
Select keyCol1,col1,col2,col3,...)
from SouceTable as s
left outer join DestTable as d on d.KeyCol1=s.KeyCol1
where d.KeyCol1 is null
and ...
ROLLBACK
another way would be a TSQL merge, google that if you need to also update and optionally delete...