I would ask help because I can not understand how to solve a problem related to a table that manages periods of different dates (also non contiguous and overlap). I would like to rebuild these periods (or to expand these lines), using existing dates, even when the attribute shown is the same.
I tried to help me with adding two index (from 0 and from 1) but I can not understand the logic to apply.
Can you please help me?

Here below an example that can better explain my problem.
Click image for larger version. 

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Thanks again for the support