SQL計數和組副本

Question

請提供解決我的問題的最佳方法。

我有一個問題搞清楚如何計算重複表像下面

Street  | City 

avenue 123 | New York 
avenue 123 | New York 
avenue 20 | New York 
avenue 35 | Chicago 
avenue 12 | Chicago 
avenue 123 | Chicago 
avenue 12 | Chicago 
avenue 12 | Chicago 

我想有在同一個城市，如下結果重複街道的號碼是多少？

結果：

Street  | City | Duplicates 

avenue 123 | New York | 2 
avenue 12 | Chicago | 3 

Answer 1

使用GROUP BY，COUNT和HAVING：

SELECT Street, City, COUNT(*) 
FROM yourtable 
GROUP BY Street, City 
HAVING COUNT(*) > 1 

看到它聯機工作：sqlfiddle

Answer 2

嘗試：

SELECT street, city, COUNT(*) AS duplicates 
FROM yourtable 
GROUP BY street, city 
HAVING COUNT(*) >1 

刪除HAVING COUNT(*) > 1如果你想顯示沒有重複的行。