Question

我想弄清楚如何选择一个表格，其值是付费最高的人的身份。

所以，如果我有

表= theJobs

JobID  Pay
----------
12345  10  
12346  12  
12347  13

table = thePerson

Person   JobID   
--------------
Person1  1  
Person2  2  
Person3  3

table = hire（FKs）

JobID  PersonID
----------------
12345  2  
12347  1  
12346  3

我希望它显示最高付费人员，以便显示

Person1

我试图使用Max函数的位置，但似乎失败了。我对这些小组的功能非常苛刻。我想我更多地问如何使用组函数作为约束而不是任何东西。因为我之前有类似的问题。

Answer 1

SELECT p.Person
FROM person p JOIN hire h ON p.PersonID = h.PersonID
  JOIN theJobs j ON h.JobID = j.JobID
ORDER BY j.Pay DESC
LIMIT 1;

如果您使用的RDBMS不支持LIMIT子句，请尝试使用TOP子句：

SELECT TOP 1 p.Person
FROM person p JOIN hire h ON p.PersonID = h.PersonID
  JOIN theJobs j ON h.JobID = j.JobID
ORDER BY j.Pay DESC

Answer 2

此解决方案几乎适用于任何数据库系统：

Select ....
From thePerson As P
    Join    (
            Select H1.PersonId, Max( J1.Pay ) As MaxPay
            From hire As H1
                Join theJobs As J1
                    On J1.JobId = H1.JobID
            Group By H1.PersonId
            ) As PayPerPerson
        On PayPerPerson.PersonId = P.Person
Where Exists    (
                Select 1
                From hire As H2
                    Join theJobs As J2
                        On J2.JobId = H2.JobID
                Where H2.PersonId = P.Person
                Having Max( J2.Pay ) = PayPerPerson.MaxPay
                )

如果您使用的是支持排名函数和公用表表达式（如SQL Server 2005及更高版本）的DBMS，那么问题就更容易了。此解决方案将仅显示一个名称并忽略关系：

With RankedPay As
    (
    Select  ...
        , Row_Number() Over( Order By J.Pay Desc ) As Rnk
    From thePerson As P
        Join hire As H
            On H.PersonId = P.Person
        Join theJobs As J
            On J.JobId = H.JobId
    )
Select ...
From RankedPay
Where Rnk = 1

此解决方案将显示与最高薪酬匹配且包含关系的任何内容：

With RankedPay As
    (
    Select  ...
        , Rank() Over( Order By J.Pay Desc ) As Rnk
    From thePerson As P
        Join hire As H
            On H.PersonId = P.Person
        Join theJobs As J
            On J.JobId = H.JobId
    )
Select ...
From RankedPay
Where Rnk = 1

Sql得到MAX其他值

2 个答案: