Raw query must include the primary key - django

Question

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])
The result of this SQL statement (tested on database directly) is:
ID | CHARACTER_ID | MESSAGE | OCCURENCES
----+--------------+---------+--------------
148 | 10 | test | 133
But all I got is a InvalidQuery Exception with the information Raw query must include the primary key
Then I double checked the docs and read:
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.
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])

Answer 1

Include 1 as id to your query
Message.objects.raw('''
SELECT 1 as id , 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])

Answer 2

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

Answer 3

Make Sure the primary key is part of the select statement.
Example:
This will not work:
`Model.objects.raw("Select Min(id), rider_id from Table_Name group by rider_id")`
But this will work:
`Model.objects.raw("Select id, Min(id), rider_id from Table_Name group by rider_id")`

Answer 4

For those also stuck with this problem, perhaps like me, wondering why Django needs a pk, when you don’t have a pk for the query (eg you want multiple rows) – Django just needs an id field returned, the pk does not need to be part of a where clause. ie:
select * from table where foo = 'bar';
or
select id, description from table where foo = 'bar';
Both of these work, if there is a field id in the table. But this throws the error described by Thomas Schwärzl, because no id field is returned:
select description from table where foo = 'bar';