Updating date field based on Date input into another date field

[Douglas_Roberts]

Hi

This should be really basic but I can’t for the life of me figure out how to do it.

I have two 4 dates fields, planned start, actual start, due date and actual completion date.

I want to be able to update the actual start date based on the completion date of the previous task. Surely this can be done?

Also

I am trying to write an IF formula that says

IF actual start date is greater than the planned start date return “delayed start”
and IF the actual start date is blank and the planned start date is greater than today, return “delayed start”

Thanks

Doug

[W_Vann_Hall]

Unfortunately, it takes a little work to get Airtable to do any sort of cross-record calculation — and often you’ll have to perform a manual or automated copy/paste to keep from triggering Airtable’s protections against circular references. The following post and associated base provides all the gory details:

Multi-record calculations (c.f. 'running balance,' 'row number,' and the like) Show and tell

tl;dr version: A frequent query and/or complaint concerns users who wish to access data from a record for use in a calculation performed in a different record from the same table. Often this takes the form of a user asking ‘how to retrieve a value based on row number’; other times the user wishes to perform a calculation that assumes knowledge of the previous record — for instance, maintaining a running balance. A recently published base contains four approaches to this problem, three involving …