create database mysqltest1;
create table mysqltest1.t1 (i int, j int as (i) persistent);
show create table mysqltest1.t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` int(11) DEFAULT NULL,
  `j` int(11) GENERATED ALWAYS AS (`i`) STORED
) ENGINE=MyISAM DEFAULT CHARSET=latin1
alter table mysqltest1.t1 add index (i);
show create table mysqltest1.t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` int(11) DEFAULT NULL,
  `j` int(11) GENERATED ALWAYS AS (`i`) STORED,
  KEY `i` (`i`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop database mysqltest1;