I think FULL OUTER JOIN is what you need here:

SELECT
    COALESCE(sales.mth, receipts.mth) AS mth,
    COALESCE(sales.yr, receipts.yr) AS yr,
   ...

Correct.  We never do multiple named instances on a server.  Heh... they still haven't found the body of the last person that tried to do that on our servers....

SQL Server will install some things on the C: / main Windows drive regardless of what you do.

The windows teams have a nasty habit of installing SQL Server on...

Better to script out the indexes; sp_helpindex doesn't show INCLUDEd columns, for one major failing.

A simple sys.sp_helptext on the view to show us its definition is fine.

You could do some major clean up on your existing code:

...6. Since Write_Error_Log is called *so many* times, need to see the code for it too. It needs to...

It also looks like you're querying a view for oeordlin rather than the actual table.  If you are using a view, the text for that view would help us a...

Presumably yes, for the same reason.  The total I/O will be spread across two files rather than one.

SELECT LEFT(first_name, 10) + CASE WHEN LEN(first_name) > 10 THEN '...' ELSE '' END AS first_name 
FROM @t1

I've noticed, and been impressed by, the overall great performance of the ROW_NUMBER() functions.

It's still a falsehood.  The docs say it is the "false_value", but the result is not "false".  ELSE is accurate, because that simply means the WHEN condition was...

Like a COALESCE with 10 arguments,...

The rule for SQL expressions and functions is that if a NULL value goes in, a NULL value comes back, unless you explicitly do something to change that.

IIF violates, in...

Like a COALESCE with 10 arguments, for example....

CLR functions for performing Regular Expression searches aren't SQL either, but they're useful. Where do you draw the line?

IIF is part of T-SQL and is more succinct...

You should just be able to add this to the end of your existing calc:

(DATEDIFF...
- (SELECT COUNT(*) FROM dbo.Holidays H WHERE H.date BETWEEN JobStartDate AND JobEndDate)
AS ...