sql使用count與group by和

當涉及到編寫涉及聚合函數（如Count和使用Having）的查詢時，我遇到了麻煩。我有兩張人名（id和name）和書籍（bookid，author_id，title）（這裏的author_id是People id的外鍵）。我目前有一個查詢，返回給我所有寫過書的人（不是所有的人都寫了一本書）。sql使用count與group by和

SELECT People.name, 
     Books.title 
FROM People, 
    Books 
WHERE Books.author_id = People.id;

現在我試圖找到只有誰寫了200多本書，並把它選擇相同的信息（people.name和books.title）的人，但我很困惑，我怎麼會去這個。我一直在嘗試使用HAVING count（People.name）> 1，但我得到的選擇絕對不正確。

新的使用sql的排序，特別是當涉及到這些額外的參數在我的查詢，只是想知道如果有人可以幫我。我沒有真正看到這些條件下的任何查詢的例子。

來源

2013-06-30 user2532770

這是更好地加入你的表是這樣的：

SELECT People.name, Books.title 
FROM People INNER JOIN Books ON Books.author_id = People.id;

，你可以添加你HAVING子句，因爲這：

SELECT Books.author_id 
FROM Books 
GROUP BY Books.author_id 
HAVING COUNT(*)>=2

然後選擇你需要，你可以用這個的所有信息：

SELECT People.name, Books.title 
FROM People INNER JOIN Books ON Books.author_id = People.id 
WHERE People.ID IN (
    SELECT Books.author_id 
    FROM Books 
    GROUP BY Books.author_id 
    HAVING COUNT(*)>=2 
)

來源

2013-06-30 14:09:47 fthiella

SELECT People.name, 
     Books.title 
FROM People, 
    Books 
WHERE Books.author_id = People.id 
    and exists (select 1 
       from (
       SELECT People.name name 
       FROM People, 
         Books 
       WHERE Books.author_id = People.id 
       group by Pepole.name 
       having count(People.name)>1 
      ) temp 
       where temp.name = People.name)

來源

2013-06-30 14:10:45 user2536579

sql使用count與group by和

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