#27685
}
        else if (nested->lowCardinality())
        {
            ColumnPtr nested_nullable = tryConvertColumnToNullable(nested);
            if (nested_nullable)
                return ColumnConst::create(nested_nullable, col_const->size());
        }
    }
    return nullptr;
}
void convertColumnToNullable(ColumnWithTypeAndName & column)
{
    if (!column.column)
    {
        column.type = convertTypeToNullable(column.type);
        return;
    }
    ColumnPtr nullable_column = tryConvertColumnToNullable(column.column);
    if (nullable_column)
    {
        column.type = convertTypeToNullable(column.type);
        column.column = std::move(nullable_column);
    }
}
void convertColumnsToNullable(Block & block, size_t starting_pos)
{
    for (size_t i = starting_pos; i < block.columns(); ++i)
        convertColumnToNullable(block.getByPosition(i));
}
void removeColumnNullability(ColumnWithTypeAndName & column)