Welcome to the community, @Sarah_Esteves1!
Unfortunately, unlike most database apps and spreadsheet apps on the market, Airtable does not support “global fields”, which is what you are looking for. A “global field” is one single field that can be seen & used by all other records in your base.
Be sure to email support@airtable.com to request that they support global fields. Airtable almost never honors customer requests, but it’s probably still a good idea to get your email into their queue (in case Airtable gets better management in the future, fingers crossed).
But you can hack your way to a global field with a workaround.
You can do this by creating a “utility table”, meaning that you create a table that only has ONE RECORD in it. This ONE record will have your ONE date field in it that you would like to be seen globally/universally.
Then, in your normal table of records, you would need to add a linked record field that points to that utility table.
The tricky/workaround/hack part is that you then need to make sure that 100% of your past & future records in your normal table always link to that ONE DATE RECORD.
You can update all of your past records by using the Batch Update extension. For all of your future records, you would need to create an automation that updates the linked record field upon creation of a new record.
Once all of your records in your normal table are linked to the one date record, you may need to take one extra step of creating a lookup field in your normal table that looks up the date field (or a rollup field that rolls up the date field with the formula values
). These fields will show you the same date for every record in your normal table, and you can use these fields in formulas as well.