CREATE TABLE Documents_Mailed (document_id VARCHAR)
CREATE TABLE Addresses (document_id VARCHAR)

What address was the document with id 4 mailed to?
SELECT Addresses.address_details FROM Addresses JOIN Documents_Mailed ON Documents_Mailed.mailed_to_address_id = Addresses.address_id WHERE document_id = 4
SELECT "Addresses"."address_details" FROM "Addresses" JOIN "Documents_Mailed" ON "Addresses"."address_id" = "Documents_Mailed"."mailed_to_address_id" WHERE "document_id" = 4