the select clause after union all has many same name columns needn't use different aliases

[l1t1]

Is your feature request related to a problem or challenge?

now it reports an error

> select 1 a,2 b union all select null,null;
Error during planning: Projections require unique expression names but the expression "NULL" at position 0 and "NULL" at position 1 have the same name. Consider aliasing ("AS") one of them.
> select 1 a,2 b union all select 2,2;
Error during planning: Projections require unique expression names but the expression "Int64(2)" at position 0 and "Int64(2)" at position 1 have the same name. Consider aliasing ("AS") one of them.

Describe the solution you'd like

It runs as normal
the result of above query equals to select 1 a,2 b union all select null,null c and select 1 a,2 b union all select 2,2 c

Describe alternatives you've considered

No response

Additional context

No response