If they are defined, they can override table-level settings.
if (has_count)
    {
        for (const auto & part : real_parts)
        {
            auto & column = assert_cast<ColumnAggregateFunction &>(*partition_minmax_count_columns.back());
            insert(column, part->rows_count);
        }
    }
    block.setColumns(std::move(partition_minmax_count_columns));
    Block res;
    for (const auto & name : required_columns)
    {
        if (virtual_columns_block.has(name))
            res.insert(virtual_columns_block.getByName(name));
        else if (block.has(name))
            res.insert(block.getByName(name));
        else if (startsWith(name, "count")) /
        {
            const auto & column = block.getByName("count()");
            res.insert({column.column, column.type, name});
        }
        else
            throw Exception(
                ErrorCodes::LOGICAL_ERROR,
                "Cannot find column {} in minmax_count projection but query analysis still selects this projection. It's a bug",
                name);
    }
    return res;
}
std::optional<ProjectionCandidate> MergeTreeData::getQueryProcessingStageWithAggregateProjection(