从SQL查询

Question

如果有一个或多个owner_ids（例如，2,4和6），我想通过resources.id返回与owners关联的owners_has_resources列表。没问题，我可以做SELECT DISTINCT ohr.resources_id FROM owners_has_resources ohr WHERE ohr.owners_id IN (2,4,6);

现在我被困住了。我想返回与上面相同的resources.id列表，但排除任何也链接到未删除链接的所有者（由owners.deleted!=true确定），其中链接未被删除（由owners_has_resources.deleted!=true）

对于所有最初提供的owners.deleted（即2,4,6），可以假设true为owners_ids

例如，给定owners_ids 2和4，我应该返回resources_id 2和3.请注意，我的意思是说deleted=TRUE表示它已被删除，但由于答案已经发布使用前面的，我不会编辑问题。相反，下面的真值表显示owner_not_deleted和resource_not_deleted。

+-----------+-------------------+--------------+----------------------+
| owners_id | owner_not_deleted | resources_id | resource_not_deleted |
+-----------+-------------------+--------------+----------------------+
|         2 | FALSE             |            1 | TRUE                 |
|         2 | FALSE             |            2 | TRUE                 |
|         4 | FALSE             |            2 | TRUE                 |
|         4 | FALSE             |            3 | TRUE                 |
|         5 | TRUE              |            1 | FALSE                |
|         5 | TRUE              |            2 | TRUE                 |
|         7 | TRUE              |            2 | FALSE                |
+-----------+-------------------+--------------+----------------------+

owners
- id (INT PK)
- name, etc
- deleted (true/false)

resources
- id (INT PK)
- name, etc

owners_has_resources
- owners_id (INT PK REFERENCES owners.id)
- resources_id (INT PK REFERENCES resources.id)
- deleted (true/false)

Answer 1

怎么样？

SELECT DISTINCT ohr.resources_id 
FROM owners_has_resources ohr 
JOIN owners o ON ohr.owners_id = o.id
WHERE ohr.owners_id IN (2,4,6)
AND (o.deleted = FALSE OR ohr.deleted = FALSE);

Answer 2

首先，您选择所需的数据，然后只选择NOT EXISTS块中未被删除的所有者引用的数据

SELECT DISTINCT ohr.resources_id 
FROM owners_has_resources ohr 
JOIN owners o ON ohr.owners_id = o.id
WHERE ohr.owners_id IN (2,4,6)
AND NOT EXISTS (
    SELECT NULL FROM owners_has_resources ohr2 
    JOIN owners o2 ON ohr2.owners_id = o2.id
    WHERE ohr2.deleted=FALSE 
    AND o2.deleted=FALSE
    AND ohr.resources_id=ohr2.resources_id 
)

Answer 3

SELECT DISTINCT ohr1.resources_id
FROM owners_has_resources ohr1
LEFT OUTER JOIN owners_has_resources ohr2 ON ohr2.resources_id=ohr1.resources_id AND ohr2.deleted = TRUE
LEFT OUTER JOIN owners o ON o.id=ohr2.owners_id AND ohr2.deleted = TRUE
WHERE ohr1.owners_id IN (2,4,6) AND o.id IS NULL;

或

SELECT DISTINCT ohr1.resources_id
FROM owners_has_resources ohr1
LEFT OUTER JOIN owners_has_resources ohr2 ON ohr2.resources_id=ohr1.resources_id
LEFT OUTER JOIN owners o ON o.id=ohr2.owners_id
WHERE ohr1.owners_id IN (2,4,6) AND o.id IS NULL AND ohr2.deleted = TRUE AND ohr2.deleted = TRUE;

对于一种方法是否优于另一种方法，我将不胜感激。