Minimum Rights Required to Compare Schemas
For successful and reliable schema comparison, you need to grant at least the Read privilege for the following objects.
A person, who performs comparison, should have the following privileges:
grant select on *.* to '<user_name>'@'%';
grant show view on *.* to 'user_name'@'%';
grant event, trigger on *.* to 'user_name'@'%';