text: --+ holdcas on;
  ---- ALTER TABLE ...  CHANGE COLUMN  , type change
  -- constraints : no constraints
  -- ordering : no order defined
  -- name : same name
  -- permissive conversion
  
  set system parameters 'alter_table_change_type_strict=yes';
  set system parameters 'error_log_level=warning';
  set system parameters 'error_log_warning=yes';
  
  -------------- varchar 1 : precision increase
  create table t1 (s1 varchar(10));
  insert into t1 values ('123'),('1234567890'),('abc');
  
  select * from t1 order by 1; 
  show columns in t1;
  
  alter table t1 change s1 s1 varchar(200);
  select * from t1 order by 1;
  show columns in t1;
  
  drop table t1;
  
  
  -------------- varchar 2 : precision decrease
  create table t1 (s1 varchar(10));
  insert into t1 values ('123'),('1234567890'),('abc');
  
  select * from t1 order by 1;
  show columns in t1;
  
  alter table t1 change s1 s1 varchar(5);
  select * from t1 order by 1;
  show columns in t1;
  
  drop table t1;
  
  -------------- varchar 3 : to set : incompatbile
  create table t1 (s1 varchar(10));
  insert into t1 values ('123'),('1234567890'),('abc');
  
  select * from t1 order by 1;
  show columns in t1;
  
  alter table t1 change s1 s1 set(varchar(10));
  select * from t1 order by 1;
  show columns in t1;
  
  drop table t1;
  
  set system parameters 'alter_table_change_type_strict=no';
  
  
  
  commit;
  --+ holdcas off;
  