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在下面的查询中，我的原始 ERD 中有 5 个表。该查询旨在从 Homes 表中选择房屋，并从相应的表中选择其特征和类型。我遇到的问题是在输入查询的特定日期范围之间选择预订表中不存在的房屋。

 Bookings  >--  Home  >--  Home_Type
                  |
                  ^
            Home_Feature
                  V
                  |
               Feature


SELECT homes.home_id, 
    homes.title, 
    homes.description, 
    homes.living_room_count, 
    homes.bedroom_count, 
    homes.bathroom_count, 
    homes.price, homes.sqft,
    listagg(features.feature_name, '\n') WITHIN GROUP(ORDER BY features.feature_name) features, 
    home_type.type_name
FROM homes
INNER JOIN home_feature 
  ON homes.home_id = home_feature.home_id
INNER JOIN home_type 
  ON home_type.type_code = homes.type_code
INNER JOIN features 
  ON home_feature.feature_id = features.feature_id
WHERE NOT EXISTS (SELECT home_id
                  FROM bookings b
                  WHERE b.home_id = homes.home_id 
                  AND (b.booking_end <= to_date('25-Jan-13') OR b.booking_end >= to_date('21-Jan-13'))
                  AND (b.booking_start <= to_date('25-Jan-13') OR b.booking_start >= to_date('21-Jan-13')))
GROUP BY homes.home_id, homes.title, 
    homes.description, homes.living_room_count, 
    homes.bedroom_count, homes.bathroom_count, 
    homes.price, homes.sqft, home_type.type_name

现在，我的查询似乎没有正确获得正确的行。下面是一个示例输出以及当前在 bookings 表中的内容，您可以看到返回的行不正确。

输出：

Home_ID    Title    Description    LivingRooms    Bedrooms    Bathrooms    Price    SQFT    Type    Features
3          Home A   A House        2              2           2            200      500     Flat    TV...
4          Home B   B House        3              1           1            250      600     House   Pool...

预订表：

Home_ID    Booking_ID    Customer_ID    Booking_Start    Booking_End
1          1             1              22-Jan-13        23-Jan-13
2          2             3              27-Jan-13        29-Jan-13

家园表：

Home_ID    ....
1          ....
2
3           
4

显然，此时查询的输出也应该包括 Home_ID 2 但不是，但我的印象是查询应该可以工作？

目前的查询应该是这样的：

Home_ID    Title    Description    LivingRooms    Bedrooms    Bathrooms    Price    SQFT    Type    Features
2          Home 2   2 House        3              1           1            100      300     Flat    Balcony...
3          Home 3   3 House        2              2           2            200      500     Flat    TV...
4          Home 4   4 House        3              1           1            250      600     House   Pool...

谁能帮我修改查询以便工作并包含正确的行？

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1 回答 1

2

我认为您想要 aleft outer join而不是where not exists.

尝试这个：

...
INNER JOIN features 
  ON home_feature.feature_id = features.feature_id
left outer join bookings b
  on homes.home_id = b.home_id
where (
        (b.booking_end <= to_date('25-Jan-13')
         OR b.booking_end >= to_date('21-Jan-13')
        )
        AND
        (b.booking_start <= to_date('25-Jan-13')
         OR b.booking_start >= to_date('21-Jan-13')
        )
      )
      or b.home_id is null
...

这将返回未预订的or b.home_id is null房屋 ( ) 和预订符合您条件的房屋。

现在应该返回所有四个房屋。

于 2013-01-24T11:45:05.807 回答