Sql 查找与Oracle中多个列值关联的列值

我在oracle中有一个具有非唯一列值的表。这些组合也是非唯一的。但特定顺序的关联必须是唯一的。我试过很多解决办法。问题是最接近的，但我需要在Oracle SQL中找到解决方案。下面是我的桌子

--------------------------------------------------
  Teacher           subject             class_id
--------------------------------------------------
    Paul              English              001
    Paul              English              002
    Allen             English              003
    Sia               Maths                134
    John              Computer             913
    Jack              Physics              341
    Arlene            Maths                001
 -------------------------------------------------

查询应仅返回以下信息

English, Maths

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i、 e与多个教师关联的科目。

如果我理解正确，您希望科目有多个教师。这是一个带有having子句的简单聚合查询：

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如果我理解正确的话，你需要有不止一位老师的科目。这是一个带有having子句的简单聚合查询：

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也许你想要这样的东西：

select listagg (subject, ', ') within group (order by subject) subjects
from (
    select subject from classes 
    group by subject
    having count(teacher)>1
);

SUBJECTS                                                                       
-------------------------
English, Maths   

或者，您也可以使用分析函数获得相同的结果：

select listagg (subject, ', ') within group (order by subject) subjects
from (
    select subject,
    count(teacher) over (partition by subject) teachers,
    row_number() over (partition by subject order by class_id) rn 
    from classes
)
where teachers>1 and rn=1
;

---

也许你想要这样的东西：

select listagg (subject, ', ') within group (order by subject) subjects
from (
    select subject from classes 
    group by subject
    having count(teacher)>1
);

SUBJECTS                                                                       
-------------------------
English, Maths   

或者，您也可以使用分析函数获得相同的结果：

select listagg (subject, ', ') within group (order by subject) subjects
from (
    select subject,
    count(teacher) over (partition by subject) teachers,
    row_number() over (partition by subject order by class_id) rn 
    from classes
)
where teachers>1 and rn=1
;