A CTE would be a better option:
WITH AboveAvg AS (
  SELECT ID, [Open_Time],
             CASE WHEN [Open_Time] > AVG([Open_Time]) OVER () * 1.5 THEN...

This might help you get started. I've annotated it, so please ask any questions. This isn't tested, however, as I did this on our Sandbox Instance, and I haven't set...

This doesn't explain...

Welcome to SSC.

Normally when posting T-SQL queries, the best way is to provide DDL, DLM and Expected output in consumable formats (have a look at the link in...

I'd hazard a guess it's the language of the connection you're using. On one it's set to (at a guess) English, but on the other something else (non English).

Without Sample data we can't write a query, however, one option is to use a CTE and put row numbering in, and then LEFT JOIN to Row Number 1. An...

Do you have any kind of key? How do we determine what rows are linked to which in your data, as it currently appears to be unordered.

Once we...

This is possible yes, but who will be doing the update? You're either going to need to give ever Login/Role that might update the record permission to send emails via...