返回多个值的Max函数[SQL]

我有三张桌子：钱、学生、教员。此查询返回每个教员及其最高津贴

select 
    f.name as "FACULTY_NAME",
    max(stipend) as "MAX_STIPEND"
from 
    money m, student s 
inner join
    faculty f on f.id_faculty = s.faculty_id
where 
    m.student_id = s.id_student
group by 
    f.id_faculty, f.name;

查询工作正常：

FACULTY_NAME     |    MAX_STIPEND
-----------------+---------------
IT Faculty       |    50
Architecture     |    60
Journalism       |    40

然而，当我将s.name添加到原始查询中以同时显示收到最高助学金的学生的姓名时，查询的工作方式与以前不同-它返回所有学生

select 
    f.name as "FACULTY_NAME",s.name,
    max(stipend) as "MAX_STIPEND"
from 
    money m, student s 
inner join
    faculty f on f.id_faculty = s.faculty_id
where 
    m.student_id = s.id_student
group by 
    f.id_faculty, f.name, s.name;

查询结果：

FACULTY_NAME    |   s.name  |   MAX_STIPEND
----------------+-----------+---------------
IT Faculty      |   Joe     |   50
IT Faculty      |   Lisa    |   10
Architecture    |   Bob     |   60
Journalism      |   Fred    |   5
Architecture    |   Susan   |   5
Journalism      |   Tom     |   40

它使用右连接、左连接和内连接执行相同的操作。有人能说出问题出在哪里吗

然而，当我将s.name添加到原始查询中以同时显示收到最高助学金的学生的姓名时，查询的工作方式与以前不同-它返回所有学生

select 
    f.name as "FACULTY_NAME",s.name,
    max(stipend) as "MAX_STIPEND"
from 
    money m, student s 
inner join
    faculty f on f.id_faculty = s.faculty_id
where 
    m.student_id = s.id_student
group by 
    f.id_faculty, f.name, s.name;

添加

s.name

时，您正在查找每个用户的最小值

如果您想知道拥有

MAX_-inspend

津贴的用户的姓名，您应该转到窗口函数。例如，在MS SQL Server中

with cte as
(select 
    f.name as "FACULTY_NAME",
    s.name as "STUDENT_NAME",
    stipend as "MAX_STIPEND",
    DENSE_RANK() OVER   
    (PARTITION BY f.name, s.name ORDER BY i.stipend DESC) AS Rank  
 from 
    money m 
 inner join student s on m.student_id = s.id_student
 inner join
    faculty f on f.id_faculty = s.faculty_id
)
select "FACULTY_NAME", "STUDENT_NAME"
from cte
where rank = 1

---

并非所有sql品牌都有窗口函数。这里是的链接，也是

首先，您应该为所有联接使用正确的

JOIN

语法

其次，您可以使用Oracle的

keep

语法：

select f.name as FACULTY_NAME,
       max(stipend) as MAX_STIPEND,
       max(s.name) keep (dense_rank first order by stipend desc)
from money m join
     student s 
     on  m.student_id = s.id_student join
     faculty f
     on f.id_faculty = s.faculty_id   
group by f.id_faculty, f.name;

---

首先，选择一种连接语法并坚持使用它。最好是使用JOIN关键字的。左对齐SQL太难阅读了。您通常按照所选的列进行分组，除了那些作为设置函数参数的列。您使用的是哪种rdbms？我使用oracle SQPLUSLL time向您@gordonLinoff学习。回答得好<代码>保留。美好的