You will not be able to accomplish what you want by unpivoting columns. However, you can:
Go to your Date table, add Custom Index Column, Starting Index 0, Increment 0
Go back to your Query, add Custom Index Column, Starting Index 0, Increment 0
Merge Date table into your Query using those two new columns; use Left Outer join
After expanding, you will have all of the rows from your Date table available.
Add Conditional Column, “Custom”, each if ([Joined]›=[From] and [Joined] ‹= [To]) then “keep” else “delete”
Filter Custom and keep only “keep”
Delete all the unnecessary columns.
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