Let's say a user creates a Google account using johndoe@example.comSoon after, the same user creates a new Google account, but instead of using the old email, creates a Gmail address. Now the user has two accounts, one logs in using johndoe@example.com, the other is johndoe@gmail.comSince the @gmail.com account only has Gmail, and everything else is on the @example.com account, is there a way to merge them?
Merging Google account with Gmail to another Google account without Gmail
gmail;google;account management
From Merging accounts FAQ on Google support site:It isn't currently possible to merge separate Google Accounts.  However, if you'd like transfer your data from one account to another,  this may be done on a per product basis. Or, to start using a new  product, you don't have to create another Google Account. Just sign in  with your existing Google Account, and visit this list of products to  get started.If you don't have Gmail, you can add it to your account at any time.If you signed up for Gmail and didn't add it to your existing account,  now you have two separate accounts.