Function formatConstant

src/Processors/QueryPlan/QueryPlanFormat.cpp:202–226

        }

        String formatConstant(const ActionsDAG::Node * node)
        {
            if (!node->column)
                return node->result_name;

            if (node->result_type && WhichDataType(node->result_type).isSet())
                return node->result_name;

            /// node->column is a size-0 ColumnConst; read the value from its data column.
            const auto & data_col = node->column->getDataColumnPtr();
            WhichDataType data_type(node->result_type);

            if (data_type.isDateOrDate32OrTimeOrTime64OrDateTimeOrDateTime64())
            {
                WriteBufferFromOwnString buf;
                writeChar('\'', buf);
                node->result_type->getDefaultSerialization()->serializeText(*data_col, 0, buf, {});
                writeChar('\'', buf);
                return buf.str();
            }

            Field value;
            data_col->get(0, value);
            return applyVisitor(FieldVisitorToString(), value);
        }

        String getRuntimeFilterId(const ActionsDAG::Node * node)
        {