Fixed #23758

- intentional breakage with recursion limit
- extents the alphabet ( to use multi letter ) for get alias prefix

executed from `test_subquery_condition` (queries.tests.Queries1Tests)
I may be missing something, but it seems this line could be bumped out one indent - no point in re-setting `prefix` to None on every product, when it won't be used again until the next outer (count) loop.