`UNION ALL` on a table and a table with no rows adds a row of `NULL`s

[KyGost]

[KyGost]

Specifically when table has been grouped as grouping outputs NULLs....

[KyGost]

For now: Removing the created row, not sure if it was there for a good reason or not

TODO: Add more tests to cover this sort of thing

[KyGost]

Also, the fix here broke some aggregate stuffs, when COUNT would be 0, we now get no rows.