> Think about subject query i.e.
>
> insert into t
> select * from t
>
> Ann talk about more complex query, but actual problem is in the subject of topic

Right, Ann described two different problems.
And the one from subject affects only those sinners who use
"unrecommended" "*" and who do not use primary key constraint.
Perhaps the example should be

insert into t (id, x)
select gen_id(g,1, x) from t

Ivan