SELECTs alone can't deadlock.

The statements you see in the deadlock graph are the ones that completed the deadlock, not all of the statements involved. From a look at...

Yes, make the column NOT NULL, then any attempt to insert/update to NULL will throw an error.

The only place where implicit conversions can cause scans is when they happen in the JOIN or WHERE clause of a statement (any statement)

@Lynn
This is how he's handling transactions: https://www.sqlservercentral.com/Forums/1893210/Are-These-Two-Code-Fragments-Equal

Anyone want to help here?
https://www.sqlservercentral.com/Forums/1893562/Using-Try-Catch-With-Stored-Procedures

I'll pass, he's taken none of the advice from the last two threads that I participated in about why the design...

Put cursor next to the * in the SELECT. Press TAB. Remove columns you don't want.

Looks more like you want a subquery, not a temp table.

Something like:

SELECT U.actionID,
   M.CardNum,
   M.serieID,
...
FROM  Upgrades U

Your code runs fine.

What version of SQL are you running?

Edit: I see what you're doing.
Table variables are batch-scoped, like normal variables. You can't create it...