Abap Syntax for a requirment

Hi experts,

What is the more convenient abap syntax to code this requirement?

What I want to do is to transfer the sold of the last year concerning an account to the current year if the key is similar of course

Example:

As you can see, line 1 and 3 of my example have the same key (in green)

So what I want to do is to calculate the summation of field Amount and report it in the next year which gives:

Summation:

Report on next year:

If not clear I can develop more.

Thanks for your help.

Amine