带有子表的 SQL 查询

Question

我有两张表 Parent 和 Child。

父表有以下列

Parent_id，姓名

子表有以下列

Parent_id（外键），Identifier，identifier_value

现在我想列出不同的 parent_id，其名称和 identifier_value（子表）对于 Identifier = "test" 具有相同的 identifier_value 但对于 Identifier = "test1" 具有不同的 identifier_value

即考虑一个例子

父表---

Parent_id, Name
1, XYZ
2, PQR

子表

Parent_id, Identifier, Identifier_value
1, test, value1
1, test1, ghght 
2, test, value1
2, test1, khkhgj

输出应该是

1, XYZ, value1, ghght
2, PQR, value1, khkhgj

它应该返回上面例子的结果，如 parent_id 1 和 2，test 具有相同的值，但 test1 具有不同的值

这是我写到现在的内容

SELECT p.parent_id,
  p.name,
  eid.identifier_value,
  eid2.identifier_value
FROM parent p,
  child eid,
  child eid2
WHERE e.parent_id             = eid.parent_id
AND e.parent_id               = eid2.parent_id
AND eid.identifier  = 'test'
AND eid2.identifier = 'test1'
AND EXISTS
  (SELECT 1
  FROM child eid3
  WHERE eid3.identifier = 'test'
  AND eid3.value                    =eid.value
  AND eid3.parent_id             <> eid.parent_id
  AND EXISTS
    (SELECT 1
    FROM child eid4
    WHERE eid4.parent_id         = eid3.parent_id
    AND eid4.identifier = 'test1'
    AND eid3.value                 <> eid4.value
    AND eid4.identifier = eid3.identifier
    )
  )

最后一个子查询中的问题。需要一些建议。

Answer 1

这是你要找的吗？

select p.*, c1.Identifier_value, c2.Identifier_value
from parent p left join
     child c1
     on c1.parent_id = p.id and c1.identifier = 'test' left join
     child c2
     on c2.parent_id = p.id and c2.identifier = 'test2'
where c1.Identifier_value <> c2.Identifier_value;

Answer 2

gordon 给出的查询有什么问题，下面是您提供的示例数据的结果。

with parent_table as
(
select 1 as parent_id, 'XYZ' as name from dual
union
select 2 as parent_id, 'PQR' as name from dual
),
child_table as 
(
select 1 as parent_id, 'test' as Identifier, 'value1' as Identifier_value from dual
union
select 1 as parent_id, 'test1' as Identifier, 'ghght' as Identifier_value from dual
union
select 2 as parent_id, 'test' as Identifier, 'value1' as Identifier_value from dual
union
select 2 as parent_id, 'test1' as Identifier, 'khkhgj' as Identifier_value from dual
)
select p.*, c1.Identifier_value, c2.Identifier_value
from parent_table p left join
     child_table c1
     on c1.parent_id = p.parent_id and c1.identifier = 'test' left join
     child_table c2
     on c2.parent_id = p.parent_id and c2.identifier = 'test1'
where c1.Identifier_value <> c2.Identifier_value;

输出与问题中的预期输出相同。

1   XYZ value1  ghght
2   PQR value1  khkhgj