If you want to query a private Google Sheet you just need to do a couple of things to enable this. These steps are outlined below. If at any time you have an issue following these steps, please reach out to [email protected].
The first step is to attach your Google Sheet's id to one of your API keys. Login to your dashboard to do this, and click on the button labeled with "Sheets".
Once you have clicked on the button you should see a screen as shown below where you can find instructions for your next steps, and where you can add your Googles Sheet id.
You can find the id in the url for the Google sheet. When viewing the sheet it will follow https://docs.google.com/spreadsheets/d/ and precede /edit/ as shown below.
The next step is to take the service account [email protected] and give it view access to the sheet you are looking to query, by clicking on the sheet's share button as shown below.
When adding you will also want to disable the "Notify people" checkbox otherwise you will get notified of the fact that the service account cannot receive emails.
At this point, you are ready to query your private Google Sheet, and as many other supported sources as you please through SQL.