Not sure just how much the real-world performance will be impacted, but the number of reads for my amended version of my query are just slightly less, as are the...

Well, I can get you down to:

Scan count 12, logical reads 12, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead...

I'm wondering if there might be a difference in the value of the environment variable somewhere.  The other possibility is that someone logged on as the user that runs these...

Your first problem is that you may not understand how triggers work, as your trigger pseudo code looks like it's only going to be able to handle single record updates,...

You are most welcome!

Try this on for size.   It just tests for existence a slightly different way, and uses UNION ALL to join the two possible sets of data.  Only one will ever...

Please post consumable information, such as CREATE TABLE statements and the INSERTS for your sample data.   You've provided expected results, but you haven't said WHY you want that particular format,...