1create table t1 (a int); 2alter table mysql.column_stats rename to mysql.column_stats1; 3flush tables; 4alter table t1 change a b varchar(100); 5show create table t1; 6Table Create Table 7t1 CREATE TABLE `t1` ( 8 `b` varchar(100) DEFAULT NULL 9) ENGINE=MyISAM DEFAULT CHARSET=latin1 10alter table mysql.column_stats1 rename to mysql.column_stats; 11drop table t1; 12