converting database of transactions to a time series

I have a database of items whether they went "in stock" or "out of stock" on a specific date. I'm trying to convert that to a table that shows for EVERY date is an item was "in stock" or "out of stock". I'm thinking my starting point is a pivot table that gets a list of horizontal list of every item in the database. But I can't figure out a formula that says for any given date, was the item in stock or not.

I've attached a simplified version of my problem, and I'd love to hear any ideas.

Thanks.