原始查询必须包含主键 [英] Raw query must include the primary key

问题描述

我在我的 views.py 中有一个原始的SQL语句

I got a raw SQL statement in my views.py

Message.objects.raw('''
        SELECT s1.ID, s1.CHARACTER_ID, MAX(s1.MESSAGE) MESSAGE, MAX(s1.c) occurrences
        FROM
           (SELECT ID, CHARACTER_ID, MESSAGE, COUNT(*) c
            FROM tbl_message WHERE ts > DATE_SUB(NOW(), INTERVAL %s DAY) GROUP BY CHARACTER_ID,MESSAGE) s1
        LEFT JOIN
           (SELECT ID, CHARACTER_ID, MESSAGE, COUNT(*) c
            FROM tbl_message WHERE ts > DATE_SUB(NOW(), INTERVAL %s DAY) GROUP BY CHARACTER_ID,MESSAGE) s2
          ON s1.CHARACTER_ID=s2.CHARACTER_ID
         AND s1.c < s2.c
        WHERE s2.c IS NULL
        GROUP BY CHARACTER_ID
        ORDER BY occurrences DESC''', [days, days])

此SQL语句的结果（直接在数据库上测试）是：

The result of this SQL statement (tested on database directly) is:

ID  | CHARACTER_ID | MESSAGE | OCCURENCES
----+--------------+---------+--------------
148 | 10           | test    | 133

但是我得到的只是一个 InvalidQuery 信息的异常原始查询必须包含主键

But all I got is a InvalidQuery Exception with the information Raw query must include the primary key

然后我重新检查了 docs ，并阅读：

Then I double checked the docs and read:

只有一个字段，您不能遗漏 - 主键
字段....如果您忘记包含主要的关键。

There is only one field that you can’t leave out - the primary key field....An InvalidQuery exception will be raised if you forget to include the primary key.

正如你所看到的，我在我的声明中添加了所请求的主键。怎么了？

As you can see I got the requested primary key added in my statement. What's wrong?

class Message(models.Model):
    character = models.ForeignKey('Character')
    message = models.TextField()
    location = models.ForeignKey('Location')
    ts = models.DateTimeField()

    class Meta:
        pass

    def __unicode__(self):
        return u'%s: %s...' % (self.character, self.message[0:20])

推荐答案

我使用Python 2.7.5，Django 1.5.1和Mysql 5.5。

I reproduced the same problem using Python 2.7.5, Django 1.5.1 and Mysql 5.5.

我将原始调用的结果保存到结果变量，所以我可以检查它包含的列：

I've saved the result of the raw call to the results variable, so I can check what columns it contains:

>>> results.columns
['ID', 'CHARACTER_ID', 'MESSAGE', 'occurrences']

ID 是大写字母，所以在您的查询中，我将 s1.ID 更改为 s1.id ，它的作品：

ID is in uppercase, so in your query I changed s1.ID to s1.id and it works:

>>> results = Message.objects.raw('''
...         SELECT s1.id, s1.CHARACTER_ID, MAX(s1.MESSAGE) MESSAGE, MAX(s1.c) occurrences
...         FROM
...            (SELECT ID, CHARACTER_ID, MESSAGE, COUNT(*) c
...             FROM tbl_message WHERE ts > DATE_SUB(NOW(), INTERVAL %s DAY) GROUP BY CHARACTER_ID,MESSAGE) s1
...         LEFT JOIN
...            (SELECT ID, CHARACTER_ID, MESSAGE, COUNT(*) c
...             FROM tbl_message WHERE ts > DATE_SUB(NOW(), INTERVAL %s DAY) GROUP BY CHARACTER_ID,MESSAGE) s2
...           ON s1.CHARACTER_ID=s2.CHARACTER_ID
...          AND s1.c < s2.c
...         WHERE s2.c IS NULL
...         GROUP BY CHARACTER_ID
...         ORDER BY occurrences DESC''', [days, days])
>>> results.columns
['id', 'CHARACTER_ID', 'MESSAGE', 'occurrences']
>>> results[0]
<Message_Deferred_character_id_location_id_message_ts: Character object: hello...>

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