Get ID alongside max value ORACLE SQL

Question

I currently have the following:

TABLE "QUARTO":

CREATE TABLE Quarto (
  Id                        number(2) NOT NULL, 
  LotacaoMaxima             number(1) NOT NULL, 
  TipoQuartoId              number(1) NOT NULL, 
  NumeroQuartoNumSequencial number(3) NOT NULL, 
  NumeroQuartoAndarId       varchar2(1) NOT NULL, 
  PRIMARY KEY (Id));

TABLE RESERVA:

CREATE TABLE Reserva (
  Id               number(3) NOT NULL, 
  ClienteNif       number(9) NOT NULL, 
  QuartoId         number(2) NOT NULL, 
  DataInicio       date NOT NULL, 
  DataFim          date NOT NULL, 
  NumPessoas       number(1) NOT NULL, 
  Estado           varchar2(15) NOT NULL, 
  DataCancelamento date, 
  PRIMARY KEY (Id));

And some data I have in both is:

QUARTO:

| ID | LOTACAOMAXIMA | TIPOQUARTOID | NUMEROQUARTONUMSEQUENCIAL | NUMEROQUARTOANDARID |
| :--- | :--- | :--- | :--- | :--- |
| 1 | 1 | 1 | 1 | 1 |
| 2 | 1 | 1 | 2 | 1 |
| 3 | 1 | 1 | 3 | 1 |
| 4 | 1 | 1 | 4 | 1 |
| 5 | 1 | 1 | 5 | 1 |
| 6 | 1 | 1 | 6 | 1 |
| 7 | 1 | 1 | 7 | 1 |
| 8 | 1 | 1 | 8 | 1 |
| 9 | 1 | 1 | 9 | 1 |
| 10 | 1 | 1 | 10 | 1 |
| 11 | 2 | 2 | 11 | 1 |
| 12 | 2 | 2 | 12 | 1 |
| 13 | 2 | 2 | 13 | 1 |
| 14 | 2 | 2 | 14 | 1 |
| 15 | 2 | 2 | 15 | 1 |
| 16 | 2 | 2 | 16 | 1 |
| 17 | 2 | 2 | 17 | 1 |
| 18 | 2 | 2 | 18 | 1 |
| 19 | 2 | 2 | 19 | 1 |
| 20 | 2 | 2 | 20 | 1 |


RESERVA:

| ID | CLIENTENIF | QUARTOID | DATAINICIO | DATAFIM | NUMPESSOAS | ESTADO | DATACANCELAMENTO |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | 296837970 | 11 | 2020-06-01 00:00:00 | 2020-06-12 00:00:00 | 1 | Finalizada | NULL |
| 2 | 275784703 | 17 | 2020-06-13 00:00:00 | 2020-06-21 00:00:00 | 1 | Finalizada | NULL |
| 3 | 220347654 | 11 | 2020-07-07 00:00:00 | 2020-07-15 00:00:00 | 2 | Finalizada | NULL |
| 4 | 294772545 | 12 | 2020-08-01 00:00:00 | 2020-08-15 00:00:00 | 2 | Finalizada | NULL |
| 5 | 220347654 | 3 | 2020-01-01 00:00:00 | 2020-01-16 00:00:00 | 1 | Finalizada | NULL |

WITH CONTAGEM_QUARTO_POR_ID AS (SELECT q.ID, COUNT(r.QUARTOID) AS NUM_RESERVAS, q.TIPOQUARTOID, q.NUMEROQUARTOANDARID
                                FROM RESERVA r
                                         INNER JOIN QUARTO q on q.ID = r.QUARTOID
                                GROUP BY q.ID, q.TIPOQUARTOID, q.NUMEROQUARTOANDARID)
SELECT t.TIPOQUARTOID, t.NUMEROQUARTOANDARID, MAX(t.NUM_RESERVAS) AS MAX
FROM CONTAGEM_QUARTO_POR_ID t
GROUP BY t.TIPOQUARTOID, t.NUMEROQUARTOANDARID

And the Output is the following:

| TIPOQUARTOID | NUMEROQUARTOANDARID | MAX |
| :----------- | :------------------ | :-- |
| 1            |                   2 |   2 |
| 2            |                   1 |   8 |
| 1            |                   1 |   1 |

I want to, alongside the data I currently have, also show toe ID of each row, but when I add the t.ID to the SELECT it forces me to add it to GROUP BY and the output is this:

| TIPOQUARTOID | NUMEROQUARTOANDARID | MAX | ID |
| :----------- | :------------------ | :-- | :- |
| 2            | 1                   | 2   | 11 |
| 1            | 1                   | 1   | 1  |
| 1            | 1                   | 1   | 3  |
| 1            | 2                   | 2   | 21 |
| 2            | 1                   | 1   | 17 |
| 2            | 1                   | 1   | 12 |
| 2            | 1                   | 8   | 16 |

I only wan to get the max value and the ID associated to that MAX.

Answer 1

You can use the KEEP clause in your query without changing it much as follows:

WITH CONTAGEM_QUARTO_POR_ID AS 
  (SELECT q.ID, COUNT(r.QUARTOID) AS NUM_RESERVAS, q.TIPOQUARTOID, q.NUMEROQUARTOANDARID
     FROM RESERVA r
     INNER JOIN QUARTO q on q.ID = r.QUARTOID
   GROUP BY q.ID, q.TIPOQUARTOID, q.NUMEROQUARTOANDARID)
SELECT t.TIPOQUARTOID, t.NUMEROQUARTOANDARID, MAX(t.NUM_RESERVAS) AS MAX, 
       max(t.ID) keep(dense_rank first order by t.NUM_RESERVAS desc nulls last) as ID -- this
FROM CONTAGEM_QUARTO_POR_ID t
GROUP BY t.TIPOQUARTOID, t.NUMEROQUARTOANDARID