SELECT  t.*
FROM    (
        SELECT  DISTINCT groupid
        FROM    mytable
        ) mo
CROSS APPLY
        (
        SELECT  TOP 1 *
        FROM    mytable mi
        WHERE   mi.groupid = mo.groupid
        ORDER BY
                age DESC
        ) t

或以下内容：

SELECT  *
FROM    (
        SELECT  *, ROW_NUMBER() OVER (PARTITION BY groupid ORDER BY age DESC) rn
        FROM    mytable
        ) x
WHERE   x.rn = 1

即使出现并列，每组也最多返回一条记录。
有关这两种方法的性能比较，请参阅我的博客中的这篇文章：

• SQL Server: Selecting records holding group-wise maximum

用途：

SELECT DISTINCT
       t.groupid,
       t.name
  FROM TABLE t
  JOIN (SELECT t.groupid,
               MAX(t.age) 'max_age'
          FROM TABLE t
      GROUP BY t.groupid) x ON x.groupid = t.groupid
                           AND x.max_age = t.age

如果一组有2个以上年龄相同的人，那又怎么样呢？最好是存储生日而不是年龄--你总是可以计算出年龄来展示。

试试这个（假设 Group 是 Household 的同义词）

Select * From Table t
Where Age = (Select Max(Age)
             From Table 
             Where GroupId = t.GroupId)

如果某个家庭中有两个或更多“最老”的人（他们都是相同的年龄，没有比他们更老的人），那么这将返回所有人，而不仅仅是随机返回一个。
如果这是一个问题，则需要添加另一个子查询，以便为该集合中的一个人返回任意键值。

Select * From Table t
Where Id = 
  (Select Max(Id) Fom Table 
   Where GroupId = t.GroupId
      And Age =
         (Select(Max(Age) From Table
          Where GroupId = t.GroupId))

SELECT GroupID, Name, Age
FROM table
INNER JOIN
(
SELECT GroupID, MAX(Age) AS OLDEST
FROM table
) AS OLDESTPEOPLE
ON
table.GroupID = OLDESTPEOPLE.GroupID
AND
table.Age = OLDESTPEOPLE.OLDEST

SELECT GroupID, Name, Age
FROM table
INNER JOIN
(
SELECT GroupID, MAX(Age) AS OLDEST
FROM table

**GROUP BY GroupID**

) AS OLDESTPEOPLE
ON
table.GroupID = OLDESTPEOPLE.GroupID
AND
table.Age = OLDESTPEOPLE.OLDEST