Function getColumnsWithSortDescription

src/Interpreters/sortBlock.cpp:102–126

using PartialSortingLessWithCollation = PartialSortingLessImpl<true>;

ColumnsWithSortDescriptions getColumnsWithSortDescription(const Block & block, const SortDescription & description)
{
    size_t size = description.size();

    ColumnsWithSortDescriptions result;
    result.reserve(size);

    for (size_t i = 0; i < size; ++i)
    {
        const auto & sort_column_description = description[i];

        auto column = block.getColumnOrSubcolumnByName(sort_column_description.column_name);

        if (isCollationRequired(sort_column_description))
        {
            if (!column.column->isCollationSupported())
                throw Exception(ErrorCodes::BAD_COLLATION, "Collations could be specified only for String, LowCardinality(String), "
                                "Nullable(String) or for Array or Tuple, containing them.");
        }

        result.emplace_back(ColumnWithSortDescription{column.column, sort_column_description, isColumnConst(*column.column)});
    }

    return result;
}

void getBlockSortPermutationImpl(const Block & block, const SortDescription & description, IColumn::PermutationSortStability stability, UInt64 limit, IColumn::Permutation & permutation)
{