set @old_debug= @@debug_dbug;
create user user_1;
show grants for user_1;
Grants for user_1@%
GRANT USAGE ON *.* TO `user_1`@`%`
# create user
create database d;
use d;

#Completely Invisible
set debug_dbug= "+d,test_completely_invisible";
create table t1(a int);
insert into t1 values(1);
select a,invisible from t1;
a	invisible
1	9
set debug_dbug=@old_debug;
grant insert(a) on t1 to user_1;
grant update(a) on t1 to user_1;
grant select(a) on t1 to user_1;
grant delete on t1 to user_1;
connect  con1, localhost, user_1,,test;
connection con1;
select user();
user()
user_1@localhost
use d;
select * from t1;
a
1
insert into t1 values(2);
select * from t1;
a
1
2
insert into t1(a) values(3);
select * from t1;
a
1
2
3
select invisible,a from t1;
ERROR 42S22: Unknown column 'invisible' in 'field list'
delete from t1 where a =1;
update t1 set a=1 where a=3;
select * from t1;
a
2
1
connection default;
REVOKE ALL PRIVILEGES, GRANT OPTION FROM user_1;
connection con1;
select * from t1;
ERROR 42000: SELECT command denied to user 'user_1'@'localhost' for table `d`.`t1`
select invisible from t1;
ERROR 42000: SELECT command denied to user 'user_1'@'localhost' for table `d`.`t1`
disconnect con1;

#Final Cleanup
connection default;
set debug_dbug= "+d,test_completely_invisible";
select a,invisible from t1;
a	invisible
2	9
1	9
drop user user_1;
drop database d;
set @old_debug= @@debug_dbug;