Using DISTINCT on mysql database with django

Question

I've been trying (and failing) to generate a query that omits results from a model without having to make a second database.

pmrs.models.LootTable

class LootTable(models.Model):
    boss = models.CharField(max_length=255)
    itemid = models.IntegerField()
    itemname = models.CharField(max_length=255)
    wfflag = models.BooleanField(help_text="Set true if warforged")

That's the model layout. What I'm trying to get is a list of everything in the boss field, but then omit the duplicates.

I've tried various different ways, .value_list, .values, order_by.().distinct etc. but nothing seems to work.

Using the following

bosses = LootTable.objects.values('boss').distinct()

Returns

[{'boss': u'Thok the Bloodthirsty'}, {'boss': u'Ordos'}, {'boss': u'Paragons of the Klaxxi'}, {'boss': u'Ordos'}, {'boss': u'Spoils of Pandaria'}, {'boss': u'Spoils of Pandaria'}, {'boss': u'Galakras'}, {'boss': u'General Nazgrim'}, {'boss': u'Ordos'}, {'boss': u'Spoils of Pandaria'}, {'boss': u'Siegecrafter Blackfuse'}, '...(remaining elements truncated)...']

As you can see from the results it's returning duplicates.

please, add your models code, and an example that what you want as result — Leandro
– Leandro, Commented Jan 28, 2014 at 16:39

Llanilek · Accepted Answer · 2014-01-28 22:51:04Z

6

You really should take the time to put the relevant pats of your model class in the question. Condensing it like you have may seem like saving time bit in reality it makes it harder to work out exactly what you're trying to do.

Based on what you have put,

q = LootTable.objects.values('boss').distinct()

should work fine. If it doesn't then something else is wrong somewhere.

As an aside, shouldn't a boss only have one loot table? Why do you need to do distinct anyway? In fact looking at the model, if I understand what you're trying to do (And there is no guarantee that I do!) I can spot quite a few issues that may bite you down the line, namely:

a) why do you have a LootTable table anyway? The same functionality could be achieved with a many-to-many foreign key between Boss and Item.

b) Why does the LootTable have both item_id and item_name on it? why not just have item be a foreign key to the Item model? (i.e. properly normalised data)

c) how is it a table if it only points to one Item? :)

edited Jan 28, 2014 at 22:51

Llanilek

3,4765 gold badges41 silver badges66 bronze badges

answered Jan 28, 2014 at 16:36

ptr

3,3942 gold badges26 silver badges50 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Llanilek Over a year ago

I did state in the original post that I'm using mysql .distinct('boss') only works with postgresql

ptr Over a year ago

then the first option should still work. See my update anyway

Llanilek Over a year ago

See my edit, the results of your original option is now in the original post. Thats the models I've been given. I don't have the option to change them.

ptr Over a year ago

any chance you could print bosses.query for that example you posted?

ptr Over a year ago

Also, you always have the option to change them. Whoever "gave" you the models looks to be trying to store relational data in a flat file database format. Using an RDBMS. Madness. :)

|

Collectives™ on Stack Overflow

Using DISTINCT on mysql database with django

1 Answer 1

7 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

7 Comments

Your Answer

Sign up or log in

Post as a guest

Related