Function extractSortColumns

src/DataStreams/LimitBlockInputStream.cpp:10–25

gets pointers to all columns of block, which were used for ORDER BY

/// gets pointers to all columns of block, which were used for ORDER BY
static ColumnRawPtrs extractSortColumns(const Block & block, const SortDescription & description)
{
    size_t size = description.size();
    ColumnRawPtrs res;
    res.reserve(size);

    for (size_t i = 0; i < size; ++i)
    {
        const IColumn * column = !description[i].column_name.empty()
                                    ? block.getByName(description[i].column_name).column.get()
                                    : block.safeGetByPosition(description[i].column_number).column.get();
        res.emplace_back(column);
    }

    return res;
}


LimitBlockInputStream::LimitBlockInputStream(