Merry Christmas everyone and a happy new year. 
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Quick thought, you could either use the ROW_NUMBER or the DENSE_RANK functions for this, just wrap the initial query in a CTE.
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You'll either need a dynamic query or if the number of distinct values are limited, use a case statement.
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CREATE TABLE #Sample (RID INT IDENTITY(1,1)...

Can you post the DDL for the table variables and some sample data as insert statements please?
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Guess you need to ask someone some questions, best bet is that it wasn't a clean install in the first place,
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Did this node have a previous live?

And the collation?
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and the server/db/table collation?
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What does this return?
SELECT
  char(249) AS FROM_CHAR
 ,char(168) AS TO_CHAR
;

What type of hardware are you running this on? 
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As I mentioned earlier, meager specs for anything in production, further, are you using a dev edition for a...

Quick thought, get a bigger server for the task, the specs are in the laptop range, not production!
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What more are you seeing in the SQL Server Error...

Quick suggestion, don't use OPENXML, you can do a straight XQuery
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DECLARE @TXML AS XML

SET @TXML = '
<appt_links>
<appt_link>
<Field name="ResourceID">38</Field>
<Field name="FromActivityID">4545</Field>
<Field...