You can use data explorer to check this. I think this query should give you a list:
old
SELECT user_id FROM facebook_user_infos
Update Feb 2019:
SELECT user_id FROM user_associated_accounts WHERE provider_name = 'facebook'
You can use data explorer to check this. I think this query should give you a list:
SELECT user_id FROM facebook_user_infos
Update Feb 2019:
SELECT user_id FROM user_associated_accounts WHERE provider_name = 'facebook'