Function getSortDescription

src/Interpreters/InterpreterSelectQuery.cpp:1045–1068

}

static SortDescription getSortDescription(const ASTSelectQuery & query, ContextPtr ctx)
{
    SortDescription order_descr;
    order_descr.reserve(query.orderBy()->children.size());
    for (const auto & elem : query.orderBy()->children)
    {
        String name = elem->children.front()->getColumnName();
        const auto & order_by_elem = elem->as<ASTOrderByElement &>();

        std::shared_ptr<Collator> collator;
        if (order_by_elem.collation)
            collator = std::make_shared<Collator>(order_by_elem.collation->as<ASTLiteral &>().value.get<String>());

        if (order_by_elem.with_fill)
        {
            FillColumnDescription fill_desc = InterpreterSelectQuery::getWithFillDescription(order_by_elem, ctx);
            order_descr.emplace_back(name, order_by_elem.direction, order_by_elem.nulls_direction, collator, true, fill_desc);
        }
        else
            order_descr.emplace_back(name, order_by_elem.direction, order_by_elem.nulls_direction, collator);
    }

    return order_descr;
}

static SortDescription getSortDescriptionFromGroupBy(const ASTSelectQuery & query)
{