GROUP BY和聚合值

Question

Id  User Val1 Val2 
11910115 Fred 123 -0.000137 
11910116 Fred 456 0 
11910117 Fred 789 0.0002 
11910118 Sue 101 8.7E-05 
11910119 Sue 102 0.000125 
11910120 Sue 103 0 

的意圖：

Select Id,User,Val1,Max(abs(val2)) val2 
From MyTable 
Group By User 

什麼我後：

11910117 Fred 789 0.0002 
11910119 Sue 102 0.000125 

我會滿足於爲：

11910117 0.0002 
11910119 0.000125 

但是，我無法避開'在選擇列表中無效，因爲它不包含在eith中呃聚合...'

Answer 1

每個非聚合的字段應該出現在組中。因此，假如你想要聚合VAL1太：

Select Id, User, max(Val1) val1, max(abs(val2)) val2 
From MyTable 
Group By Id, User 

Answer 2

SELECT y.Id, y.User, y.Val1, t.MaxVal 
    FROM YourTable y 
     INNER JOIN (SELECT User, MAX(ABS(val2)) AS MaxVal 
         FROM YourTable 
         GROUP BY User) t 
      ON y.User = t.User 
       AND ABS(y.Val2) = t.MaxVal 
    WHERE y.User = 'Fred' 

Answer 3

select Id, User, Val1, Val2 
from MyTable t1 
where not exists 
(
    select * 
    from MyTable t2 
    where t2.Id != t1.Id 
    and t2.User = t1.User 
    and abs(t2.Val2) > abs(t1.Val2) 
) 

Answer 4

試試這個

SELECT t.id, t.user, t.val1, t.val2 
FROM mytable t 
    INNER JOIN 
     (SELECT user, MAX(ABS(val2)) AS max 
     FROM mytable 
     GROUP BY user) q ON t.user = q.user AND ABS(t.val2)=q.max 

不知道如何有效的，這將是你的桌子上，雖然。

Answer 5

select Id, 
     [User], 
     Val1, 
     Val2 
from (
     select Id, 
      [User], 
      Val1, 
      Val2, 
      row_number() over(partition by [User] order by abs(Val2) desc) as rn 
     from YourTable 
     -- where ... goes here 
    ) as T 
where rn = 1 

http://data.stackexchange.com/stackoverflow/q/114300/