Calculating weeks on hand based on forecast of subsequent weeks

Hi,

I have the following dataset:

The Desired O/ P is:

The logic is as follows:

I need to calculate the number of weeks on hand for each item for that particular week based on forecast for several weeks going forward.

So  for week of Jan 28, 2019 , the Projected Inventory is 604.

In order to calculate the Weeks On hand of Item A for week of Jan 28, 2019 the calculation is as follows:

FOR WEEK OF Jan 28, 2019:

Iteration 1:

604 – 50(FC for week 1) = 554

Weeks on Hand(WOH)  = 0 + 1 = 1

Iteration 2:

554 – 52(FC for week 2) = 502

WOH = 1 + 1 = 2

Iteration 3:

502 – 49 (FC for week 3) = 453

WOH = 2 + 1 = 3

 And so on…

Finally we get WOH = 11  for Item A for week of Jan 28, 2019.

FOR WEEK OF Feb,04 2019:

Iteration 1:

650 – 52(FC for week 2) = 598

Weeks on Hand(WOH)  = 0 + 1 = 1

Iteration 2:

598 – 49(FC for week 2) = 549

WOH = 1 + 1 = 2

Iteration 3:

549 – 46 (FC for week 3) = 503

WOH = 2 + 1 = 3

 And so on…

Finally we get WOH = 12  for Item A for week of Feb 04, 2019.

Similarly I need to calculate WOH for subsequent weeks and for different items

NOTE: Also there should be at least 10 weeks of Forecast for an item , if not the WOH = 0.

How to achieve this result in My SQL?

I am thinking Stored Procedures using cursors is the way to go. However I am not really familiar with Stored Procedure.

Is there an alternate method ? Any help will be appreciated.

Thanks in advance.

Prajwal