Question

抓住我的头一天。

需要根据与电影相关的分组max（）视图，将电影和流派列表缩减为电影和流派列表。

所以转变＆＃39; a＆＃39;到＆＃39;＆＃39;这里有T-SQL
（紫色行是有效的输出表：Image）

+---------+--------------+-------+
|  Title  |    Genre     | Views |
+---------+--------------+-------+
| Mad Max | Mockumentary |     1 |
| Mad Max | Sci-fi       |   169 |
| Mad Max | Documentary  |    32 |
| Titanic | Drama        |     6 |
| E.T.    | Sci-fi       |    34 |
| E.T.    | Sci-fi       |     2 |
| E.T.    | Horror       |     1 |
| Taken   | Triller      |    60 |
| Taken   | Crime Drama  |     2 |
| Taken   | Triller      |    40 |
| Taken   | Crime Drama  |    15 |
+---------+--------------+-------+

预期结果

+---------+---------+-------+
|  Title  |  Genre  | Views |
+---------+---------+-------+
| Mad Max | Sci-fi  |   169 |
| Titanic | Drama   |     6 |
| E.T.    | Sci-fi  |    36 |
| Taken   | Triller |   100 |
+---------+---------+-------+

Answer 1

试试这个...

SELECT title, genre, views
FROM   (SELECT title, 
               genre, 
               Sum(views) AS views, 
               ROW_NUMBER() OVER (PARTITION BY title ORDER BY Sum(views) DESC) AS ranks 
        FROM   tablename 
        GROUP  BY title, genre) tmp 
WHERE ranks < 2

输出

+---------+---------+-------+
|  title  |  genre  | views |
+---------+---------+-------+
| E.T.    | Sci-fi  |    36 |
| Mad Max | Sci-fi  |   169 |
| Taken   | Triller |   100 |
| Titanic | Drama   |     6 |
+---------+---------+-------+

在线演示：http://www.sqlfiddle.com/#!18/e34fe/1/0

根据分组MAX（）减少行数

1 个答案: