Merging Separate Google Accounts

Perhaps you have read a luring article about merging Google accounts and then spent the whole night trying to do that unsuccessfully. Well, the truth is that it is not currently possible to merge separate Google Accounts. Nonetheless, as Google has pointed out in (Managing and using Google products), you can transfer data from one account to another on a per product basis. It is also advisable that if you want to use any Google product including Blogger, YouTube, Drive and Gmail, simply sign in with your existing Google Account, and chose a product from a listof products offered by Google. In case you do not have Gmail, you can add it to your Google account easily; Signing up for Gmail and failing to add it to your existing Gmail account results in two separate accounts. Also note that Google prevents you from adding  an existing Gmail username even if the account associated with the Gmail has been deleted. In other words, you can’t reuse a Gmail username.  

In case you have any doubt, take it from Google directly: https://support.google.com/accounts/answer/63304?hl=en