SET @@session.storage_engine = 'memory';
create table t1 (a int, b int as (a+1));
ERROR HY000: 'Specified storage engine' is not yet supported for computed columns
create table t1 (a int);
alter table t1 add column b int as (a+1);
ERROR HY000: 'Specified storage engine' is not yet supported for computed columns
drop table t1;