# Calculating weeks on hand based on forecast of subsequent weeks

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Hi,

I have the following dataset:

 Item Date Projected Inventory(PE) Forecast(FC) A Jan 28, 2019 604 50 A Feb 04, 2019 630 52 A Feb 11, 2019 1303 49 A Feb 18, 2019 1257 46 A Feb 25, 2019 1176 51 A Mar 04, 2019 1136 55 A Mar 11, 2019 1083 53 A Mar 18, 2019 1030 53 A Mar 25, 2019 980 50 A Apr 01, 2019 900 65 A Apr 08, 2019 853 62 A Apr 15, 2019 944 59 A Apr 22, 2019 1303 49

The Desired O/ P is:

 Item Date Weeks On Hand A Jan 28, 2019 11 A Feb 04, 2019 12 A. Feb 11, 2019 9 A Feb 18, 2019 8 A Feb 24, 2019 0 (there should be at least 10 weeks of Forecast for an item , if not the WOH = 0) A ... 0

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.

Prajwal

• Do you have access to Redshift?  Or does it need to be a MySQL dataflow?

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I have access to Redshift, yes. It does not necessarily have to be MySQL dataflow.

• I'll try to work on this tomorrow.  Can I get an idea of how many Items are in your data set?  Are you also forecasting for multiple locations?

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There are a total of 1172 Items , but all Locations aggregated for an item. So basically just 1 location.

For each item there are upto 72 weeks of data so the dataset has a total of 84K+ rows.

Thanks.

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Could someone help me out with this or provide me with some direction?