How can I further optimize a derived table query which performs better than the JOINed equivalent?

Question

UPDATE: I found a solution. See my Answer below.

My Question

How can I optimize this query to minimize my downtime? I need to update over

Answer 1

About BETWEEN

SELECT * FROM a WHERE a.column BETWEEN x AND y 

• is indexable and corresponds to a range lookup on index a.column (if you have one)
• is 100% equivalent to a.column >= x AND a.column <= y

While this:

SELECT * FROM a WHERE somevalue BETWEEN a.column1 AND a.column2

• is 100% equivalent to somevalue >= a.column1 AND somevalue <= a.column2
• is a very different thing from the first one above
• is not indexable by a range lookup (there is no range, you got 2 columns here)
• generally leads to horrible query performance

I think there was confusion about this in the debate on "between" above.

OP has the first kind, so no worry.