仅返回MySQL查询中的较高ID

Question

I have 2 tables:

___Rooms

|--------|------------|
| ROO_Id | ROO_Number |
|--------|------------|
| 22     | 101        |
| 23     | 102        |
| 24     | 201        |
|--------|------------|

___Bookings

|--------|------------|------------|------------|-------------------|
| BOO_Id | BOO_RoomId | BOO_DateCI | BOO_DateCO | BOO_ArrivalStatus |
|--------|------------|------------|------------|-------------------|
| 34     | 22         | 2018-07-17 | 2018-07-20 | checkin           |
| 35     | 23         | 2018-07-17 | 2018-07-18 | checkout          |
| 36     | 24         | 2018-07-19 | 2018-07-21 | none              | 
| 37     | 23         | 2018-07-18 | 2018-07-21 | none              | 
|--------|------------|------------|------------|-------------------|

---

My goal is to have the following report:

The date of the report is today : 2018-07-18 .

|------------|----------------|-------------------|
| ROO_Number | BOO_LiveStatus | BOO_ArrivalStatus |
|------------|----------------|-------------------|
| 101        | in-house       | checkin           |
| 102        | none           | no                |
| 201        | none           | no                |
|------------|----------------|-------------------|

---

I put a SQLFidde here : http://sqlfiddle.com/#!9/bb6a30/4

---

Actually, I'm very near but I have a little problem.

I need to have only one row per room. For room #102, I have two successive bookings and my query returns me two rows for it whereas it should return me the booking with the higher id (BOO_Id) .

---

My last try was this one:

SELECT 
    ROO_Id,
    IF(BOO_DateCI <= '2018-07-18' AND BOO_DateCO >= '2018-07-18', "in-house", "no")
        AS BOO_LiveStatus,
    IFNULL(BOO_ArrivalStatus, "0") 
        AS BOO_ArrivalStatus,
    BOO_Id,
FROM ___Rooms
LEFT JOIN ___Bookings
    ON ___Rooms.ROO_id = ___Bookings.BOO_RoomId 
        AND '2018-07-18' BETWEEN ___Bookings.BOO_DateCI AND ___Bookings.BOO_DateCO
WHERE ROO_Status != 'inactive'
ORDER BY 
  ROO_Number

Could you please help me please ?

Thanks a lot.

Answer 1

YOu should add an inner join on the max(BOO_DateCI) group by BOO_RoomId

  SELECT 
    ROO_Id,
    IF(BOO_DateCI <= '2018-07-18' AND BOO_DateCO >= '2018-07-18', "in-house", "no")
        AS BOO_LiveStatus,
    IFNULL(BOO_ArrivalStatus, "0") 
        AS BOO_ArrivalStatus,
    BOO_Id
FROM ___Rooms
inner join  (
  select  BOO_RoomId,max(BOO_DateCI) max_BOO_DateCI
  from ___Bookings
  group by BOO_RoomId

) t on t.BOO_RoomId = ___Rooms.ROO_id 
LEFT JOIN ___Bookings
    ON ___Rooms.ROO_id = ___Bookings.BOO_RoomId 
        AND '2018-07-18' BETWEEN ___Bookings.BOO_DateCI AND ___Bookings.BOO_DateCO
        AND t.max_BOO_DateCI=  ___Bookings.BOO_DateCI
ORDER BY 
  ROO_Number