sql-server - SQL 计数和分组重复

Question

请建议解决我的问题的最佳方法。

我在弄清楚如何计算下表中的重复项时遇到问题

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

我想在同一个城市有多个重复的街道，结果如下？

结果：

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

在线查看它：sqlfiddle

Answer 2

尝试 ：

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

HAVING COUNT(*) > 1如果您还想显示没有重复的行，请删除。