如何選擇最大值的行？

Question

select NATIONALPLAYERS.FIRSTNAME||' '|| NATIONALPLAYERS.LASTNAME as PlayerName, NATIONALPLAYERS.EXPERIENCEID, experience 

from NATIONALPLAYERS 

INNER JOIN (select experienceid, MAX(experiences.nationalgames + experiences.internationalgames) as experience 

from experiences 

group by experiences.EXPERIENCEID)plexperience 
on plexperience.experienceid = NATIONALPLAYERS.experienceid; 

這顯示從PlayerName，ExperienceID，並Experience即使我只要求的experience最大值的所有記錄。

Answer 1

您正在按EXPERIENCEID分組，並獲得最大EXPERIENCE爲每個人 - 你沒有找到EXPERIENCEID，其中對應的最大EXPERIENCE。

如果你想找到值最大的經驗，那麼你想要的東西，如：

SELECT * 
FROM (
    select n.FIRSTNAME ||' '|| n.LASTNAME as PlayerName 
     n.experienceid, 
     e.nationalgames + e.internationgames as Experience 
    from NATIONALPLAYERS n 
     INNER JOIN 
     EXPERIENCE e 
     ON (e.experienceid = n.experienceid) 
    ORDER BY Experience DESC 
) 
WHERE ROWNUM = 1; 

，或者，如果有多個最高行：

SELECT * 
FROM (
    select n.FIRSTNAME ||' '|| n.LASTNAME as PlayerName 
     n.experienceid, 
     e.nationalgames + e.internationgames as Experience, 
     RANK() OVER (ORDER BY e.nationalgames + e.internationgames DESC) 
      AS rn 
    from NATIONALPLAYERS n 
     INNER JOIN 
     EXPERIENCE e 
     ON (e.experienceid = n.experienceid) 
    ORDER BY Experience DESC 
) 
WHERE rn = 1; 

Answer 2

你缺少什麼最大的經驗。正在檢查的experience_id但不能確保該經驗值的最大值

查詢應該是這樣的：

SELECT 
    NATIONALPLAYERS.FIRSTNAME||' '|| NATIONALPLAYERS.LASTNAME as PlayerName, 
    NATIONALPLAYERS.EXPERIENCEID, 
    experience 

from NATIONALPLAYERS 
INNER JOIN (
    select 
     experienceid, 
     MAX(experiences.nationalgames +  experiences.internationalgames) as experience 

    from experiences 
    group by experiences.EXPERIENCEID) AS plexperience 
on 
    plexperience.experienceid = NATIONALPLAYERS.experienceid 
    **plexperience.experience = NATIONALPLAYERS.experience;**