SQL Server：获取具有附加数据的一系列值之间的最大值

Posted 2023-03-25

【中文标题】SQL Server：获取具有附加数据的一系列值之间的最大值

【英文标题】：SQL Server: get max value between a range of values with additional data

【发布时间】：2016-12-07 00:32:35

【问题描述】：

大多数人想要最大值，但我需要一个范围内的最大值加上额外的数据。例如，我有一个团队及其经理及其经理 ID 的列表。我查看了谷歌/***，但大多数人只想要最大值，但我也需要额外的列，这就是我问这个问题的原因。

表 1：

team  mgr_level mgr_id
-----------------------
aa     1          111
aa     2          222 
aa     3          333
bb     1          111
bb     2          222
cc     1          111
cc     2          222
cc     3          444 
cc     4          888 

表2：

employee       emp_id   team
------------------------------
smith, mary      23     aa
jones, john      34     bb 
ramjet, roger    98     cc
james, adam      111    mgr_team
green, rachel    222    mgr_team
bruin, breezly   333    mgr_team
runner, road     444    mgr_team
potter, harry    888    mgr_team

我需要选择介于 222 和 444 之间的最大值（mgr_id）以及其他数据（团队和 mgr_id）。

需要的结果如下所示。有没有办法一步完成而不是两步？

name           team   primary_mgr_id  manager_name
-----------------------------------------------
smith, mary     aa      333           bruin, breezly
jones, john     bb      222           green, rachel  
ramjet, roger   cc      444           runner, road

我试过了，但 SQL Server 不断为每个名称返回多行：我做错了什么？

select max(mgr_id) as [primary_mgr_id], t2.employee, t1.mgr_id
from table2 t2
inner join table1 t1 on t2.team = t2.team
group by t2.employee, t1.mgr_id

感谢您的帮助。 斯文

【问题讨论】：

我添加了它！谢谢我忘了添加它

【参考方案1】：

一个选项是借助 Row_Number()

Select Name = A.Employee
      ,A.Team
      ,primary_mgr_id = B.Mgr_ID
      ,manager_name   = B.manager_name
From  Table2 A
Join (
        Select A.*
              ,manager_name = employee
              ,RN = Row_Number() over (Partition By A.Team Order by A.mgr_level desc)
         From Table1 A
         Join Table2 B on (A.Mgr_ID=B.Emp_ID)
         Where mgr_id between 222 and 444
     ) B on A.Team=B.Team and B.RN=1 

返回

Name            Team    primary_mgr_id  manager_name
smith, mary     aa      333             bruin, breezly
jones, john     bb      222             green, rachel
ramjet, roger   cc      444             runner, road

另一种选择是使用交叉应用

Select Name = A.Employee
      ,A.Team
      ,primary_mgr_id = B.Mgr_ID
      ,manager_name   = B.employee
From  Table2 A
Cross Apply (
        Select Top 1 C.*,D.employee 
         From  Table1 C
         Join  Table2 D on (emp_id = mgr_id)
         where C.Team=A.Team and mgr_id between 222 and 444 Order by mgr_level desc
      ) B

【参考方案2】：

这是你要找的那个吗？

SELECT
    employee AS name, team, max_mgr_id AS primary_mgr_id, t3.employee as manager_name
FROM
    table2 t2
JOIN (
    SELECT team, MAX(mgr_id) AS max_mgr_id
    FROM table1
) t1 ON t2.team = t1.team
JOIN table2 t3 ON t3.emp_id = t1.max_mgr_id AND t3.team = 'mgr_team'

【参考方案3】：

我会像使用 outer apply 那样做这个

select t2.*, t1.mgr_id as primary_mgr_id , t1.name as manager_name
from table2 t2 outer apply
     (select t1.mgr_id, tt2.name
      from table1 t1 join
           table2 tt2
           on t1.mgr_id = tt2.emp_id
      where t1.team = t2.team and
            t1.mgr_id between 222 and 444
      order by t1.mgr_id desc
     ) t1;