SQL Express is limited to 1.4GB of RAM.  I'm stunned that 12,000 connections could even be initiated in that little RAM.  You need to have most of those requests somehow...

Is it possible to exit the proc without falling thru to the DROP TABLE? What about the start of the proc? If the temp table already exists, does...

Is it possible to exit the proc without falling thru to the DROP TABLE?

What about the start of the proc?

If the temp table already exists, does the proc scratch (drop...

The other issue with IIF is that it can be nested only 10 deep.  I do have some CASE conditions that have (far) more than 10 WHEN conditions.  It would...

Make sure the proc is dropping or truncating the temp table every time at the start of the proc.

It sounds as if rows from the prior run are being left...

I think we are, and hooray! for that.  From what I've read, at least, the STRING_AGG performs well.

I have only one box on 2017 right now, many on 2016 (and,...

I admit, I don't expect IIF to go away (ever), as bad an idea as it was to corrupt T-SQL with it.  I'm just hoping they don't bring over things...

I was worried about potential performance issuing in the subquery methods, at least for larger numbers of rows.

For smaller numbers of rows, the subquery may in fact perform somewhat better.

by the way, since we already have touched the subject,

is it a good idea at all to execute anything like this on a remote server as EXEC  (...)  AT...

I don't know of one.  And I don't see the value of it.  First, if the statement appears in a loop, you'd have to multiply the cost.  Second, not all...

exec ('CREATE OR ALTER PROCEDURE ins_tmp_proc AS

BEGIN

INSERT INTO dbo.tmp (job_id, name, ..., server)

SELECT job_id, name, ..., @@SERVERNAME from msdb.dbo.sysjobs

UNION ALL

SELECT job_id, name, ..., ''<remoteserver>'' from <remoteServer>.msdb.dbo.sysjobs

END')

UPDATE CT --<<-- this MUST be CT, NOT CallTable
SET Fname = ISNULL(Fname_Max, Fname), Lname = ISNULL(Lname_Max, Lname)
FROM CallTable CT
INNER JOIN (
    SELECT CallID, MAX(Fname)...

CONCAT and CONVERT do not work on conditions, i.e. comparisons.  They work on expressions, as do all SQL functions.

That's why I used IF to compare to IIF -- it's one...

CASE, ISNULL and COALESCE are all an integral part of SQL Server and follow its general syntax.  It's because IIF is so unlike other other functions and expressions...

A clustered index would be the best chance to avoid deadlocks.  So there are roughly 60K rows for each column1 value?  And you want to change all of them in...