如何編寫這條SQL語句？

Question

下面是表： 用戶

Name: Subject: 
Peter Math 
Mary Chinese 
Mary Computer 
Mary Hist 
Mary PE 
Mary English 
Peter Art 
Chris English 
Chris Computer 
Peter Computer 
Paul Math 

我想獲得的頂部出現在名稱，並返回前4的結果應該是主題名稱。例如，在這種情況下，頂部出現的名字是瑪麗，並在主題的順序基地，中國，計算機，英語，所以我想有結果：

Mary Chinese 
Mary Computer 
Mary English 
Mary Hist 

如果瑪麗是不是最足顯示結果，第二人會後續一樣，讓說，該表將是這樣的：

Name: Subject: 
Peter Math 
Mary Chinese 
Mary Computer 
Mary Hist 
Peter Art 
Chris English 
Chris Computer 
Peter Computer 
Paul Math 

其結果將是，

Mary Chinese 
Mary Computer 
Mary Hist 
Peter Art 

因爲瑪麗是最出現，所以瑪麗會回來，布瑪麗是不足以填補4個職位，所以第二個出現將佔據位置，在這種情況下，我們使用彼得。

Answer 1

 
SELECT user.name, user.subject 
FROM user 
INNER JOIN (
    SELECT name, COUNT(1) AS occurrences 
    FROM user 
    GROUP BY name 
) AS user_occurrences 
    ON user.name = user_occurrences.name 
ORDER BY user_occurrences.occurrences DESC, user.name ASC, user.subject ASC 
LIMIT 4 

編輯這可能會表現得更好，這取決於您使用的RDBMS和數據集的大小。嘗試兩者並進行比較。

 
SELECT user.name, user.subject 
FROM user 
INNER JOIN user AS user_occurrences 
    ON user.name = user_occurrences.name 
GROUP BY user.name --, user.subject Second GROUP BY not needed on MySQL, but it should logically be there 
ORDER BY COUNT(user_occurrences.subject) DESC, user.name ASC, user.subject ASC 
LIMIT 4 

Answer 2

按名稱從組中選擇前4，主題和排序算

MSSQL代碼：

select top 4 q.marketname, cc.countryname from (
select top 100 m.MarketName, m.MarketId, COUNT(m.marketname) as [count] 
from Common.Country c inner join Common.Market m on c.MarketId = m.MarketId 
group by m.MarketName, m.MarketId order by COUNT(m.marketname) desc) 
q inner join Common.Country cc 
on cc.MarketId = q.MarketId order by [Count] desc 

也可以做類似MySQL的代碼

這裏是培訓相關MySQL代碼

select q.name, cc.subject from (
    select m.Name, count(*) as Count 
    from User m 
    group by m.Name 
    order by COUNT(*) desc 
    LIMIT 100 
) q 
inner join user cc on cc.Name= q.name 
order by Count desc 
LIMIT 4 

這是很受歡迎的，你想要不費吹灰之力？你不能在你的技術中實現邏輯嗎？如果沒有理解解決方案建議，你不應該倒退。