1select @@global.explicit_defaults_for_timestamp; 2@@global.explicit_defaults_for_timestamp 30 4select @@session.explicit_defaults_for_timestamp; 5ERROR HY000: Variable 'explicit_defaults_for_timestamp' is a GLOBAL variable 6show global variables like 'explicit_defaults_for_timestamp'; 7Variable_name Value 8explicit_defaults_for_timestamp OFF 9show session variables like 'explicit_defaults_for_timestamp'; 10Variable_name Value 11explicit_defaults_for_timestamp OFF 12select * from information_schema.global_variables where variable_name='explicit_defaults_for_timestamp'; 13VARIABLE_NAME VARIABLE_VALUE 14EXPLICIT_DEFAULTS_FOR_TIMESTAMP OFF 15select * from information_schema.session_variables where variable_name='explicit_defaults_for_timestamp'; 16VARIABLE_NAME VARIABLE_VALUE 17EXPLICIT_DEFAULTS_FOR_TIMESTAMP OFF 18set global explicit_defaults_for_timestamp=true; 19ERROR HY000: Variable 'explicit_defaults_for_timestamp' is a read only variable 20set session explicit_defaults_for_timestamp=true; 21ERROR HY000: Variable 'explicit_defaults_for_timestamp' is a read only variable 22