Function executeActionForHeader

src/Interpreters/ActionsDAG.cpp:615–677

}

static ColumnWithTypeAndName executeActionForHeader(const ActionsDAG::Node * node, ColumnsWithTypeAndName arguments)
{
    ColumnWithTypeAndName res_column;
    res_column.type = node->result_type;
    res_column.name = node->result_name;

    switch (node->type)
    {
        case ActionsDAG::ActionType::FUNCTION:
        {
            // bool all_args_are_const = true;

            // for (const auto & argument : arguments)
            //     if (typeid_cast<const ColumnConst *>(argument.column.get()) == nullptr)
            //         all_args_are_const = false;

            res_column.column = node->function->execute(arguments, res_column.type, 0, true);

            // if (!all_args_are_const)
            //     res_column.column = res_column.column->convertToFullColumnIfConst();

            break;
        }

        case ActionsDAG::ActionType::ARRAY_JOIN:
        {
            auto key = arguments.at(0);
            key.column = key.column->convertToFullColumnIfConst();
            const auto * array = getArrayJoinColumnRawPtr(key.column);

            if (!array)
                throw Exception(ErrorCodes::TYPE_MISMATCH,
                                "ARRAY JOIN of not array nor map: {}", node->result_name);

            res_column.column = array->getDataPtr()->cloneEmpty();
            break;
        }

        case ActionsDAG::ActionType::COLUMN:
        {
            res_column.column = node->column->cloneResized(0);
            break;
        }

        case ActionsDAG::ActionType::ALIAS:
        {
            res_column.column = arguments.at(0).column;
            break;
        }

        case ActionsDAG::ActionType::INPUT:
        {
            break;
        }

        case ActionsDAG::ActionType::PREPARED_COLUMN:
        {
            break;