I am working on a shortage report for shop orders material. I have a concept of if full required hasn’t been issued of that material by the date required and date required < today then its fine I can mark it as a shortage, I want to look for future shortages (90 days) and I am thinking how to do that? any ideas? how can I suspect if the future date required (Say 5 days from now) the part will be on shortage or not?

The only thought I have his to check if the SO/PO is against that demand (but that too is confusing how to do..)