Question

我有一个文章表，用于存储user id，article id和article views。我希望从此表中获取所有用户，并按其总文章视图(sum) > 50订购。

见下表。

id | user_id | article_id | views
1      2          1          34
2      2          2          26
3      3          3          19
4      3          4          26
5      4          5          40
6      4          6          29

我想得到这样的东西。

user_id | views
 2          60
 4          69

Answer 1

您可能希望使用一个加重函数sum来累加视图，然后使用group by来提供所需的响应。

mysql> describe `blah`;
+------------+------------------+------+-----+---------+----------------+
| Field      | Type             | Null | Key | Default | Extra          |
+------------+------------------+------+-----+---------+----------------+
| id         | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| user_id    | int(11)          | YES  |     | NULL    |                |
| article_id | int(11)          | YES  |     | NULL    |                |
| views      | int(11)          | YES  |     | NULL    |                |
+------------+------------------+------+-----+---------+----------------+




mysql> select * from blah;
+----+---------+------------+-------+
| id | user_id | article_id | views |
+----+---------+------------+-------+
|  1 |       2 |          1 |    34 |
|  2 |       2 |          2 |    26 |
|  3 |       3 |          3 |    19 |
|  4 |       3 |          4 |    26 |
|  5 |       4 |          5 |    40 |
|  6 |       4 |          6 |    29 |
+----+---------+------------+-------+


/* use `SUM` and `GROUP BY` to give desired output */
mysql> select `user_id`, sum( `views` ) from `blah` group by `user_id`;
+---------+----------------+
| user_id | sum( `views` ) |
+---------+----------------+
|       2 |             60 |
|       3 |             45 |
|       4 |             69 |
+---------+----------------+

将记录限制在50以上

mysql> select `user_id`, sum( `views` ) as 'total' from `blah` group by `user_id` 
       having `total` > 50;
+---------+-------+
| user_id | total |
+---------+-------+
|       2 |    60 |
|       4 |    69 |
+---------+-------+

Answer 2

您需要的是GROUP BY，SUM（）和HAVING

您需要GROUP BY告诉mysql您将同一用户的条目分组到一个条目中。您需要SUM（视图）告诉mysql需要将同一用户的所有视图条目添加到一起。最后，您需要HAVING告诉mysql在逐个级别上存在需要满足的条件才能被视为有效结果。

SELECT user_id, SUM(views) AS views
FROM table GROUP
GROUP BY user_id
HAVING SUM(views) > 50

我有一个文章表，存储用户ID，文章ID和文章视图，我想检索他们大于50的ID

2 个答案: