I need to group and sort by date_published some documents stored on mongodb using pymongo.
the group part went just fine :) but when I'm addding .sort() to the query it keeps failing no matter what I tried :(
here is my query:
db.activities.group(keyf_code,cond,{},reduce_code)
I want to sort by a field called "published" (timestamp)
tried to do
db.activities.group(keyf_code,cond,{},reduce_code).sort({"published": -1})
and many more variations without any success
ideas anyone?
You can't currently do sort with group in MongoDB. You can use MapReduce instead which does support a sort option. There is also an enhancement request to support group with sort here.
Although MongoDB doesn't do what you want, you can always use Python to do the sorting:
result = db.activities.group(keyf_code,cond,{},reduce_code)
result = sorted(result, key=itemgetter("published"), reverse=True)
Related
I am trying to sort the result of my mongoDB query and add a ranking based on that sorting. Currently I only call .find().sort({total: 1}) and this gives me the correct ordering of the documents. But is it possible to "add a field" based on that sorting (basically a ranking field, starting from 1 and counting up)? I tried googling but didnt found anything that suits for this purpose.
Thanks in advance.
I am trying to execute 2 queries at the same time, for example, refer below:
db.getCollection('Test').find({'color':'red'},{'color':'yellow'});
Assume that color red is present in the one collection and yellow is present in another collection, but I am getting the response only from the first query.
Expectation:
1.If both the queries are present in any of the collection I should get both
responses.
2.If anyone of the query is invalid or element is not present in the collection,
I should not get any response.
Thanks in advance
Since you want to match existence of both values, use $all operator:
db.getCollection('Test').find({color:{$all:["red","yellow"]}})
Edit
I managed to get your output, but I think this could be simplified. I thought about different options and ended up in this query:
db.colors.aggregate([{
$facet:{
cond1:[{$match:{color:"red"}}],
cond2:[{$match:{color:"yellow"}}]
}},
{$project:{match1: "$cond1", match2:"$cond2" ,size1:{$size: "$cond1"},
size2:{$size: "$cond2"}}},
{$project:{result:{$cond:[{$and:[{$gte:["$size1",1]},{$gte:
["$size2",1]}]},{$concatArrays:["$match1","$match2"]},[]]}}}
])
I think there is something wrong with your question.
I think you are looking for something like this db.getCollection('Test').find({color: {$in: ['red','yellow']}});
I hope this will help.
I have the following problem: I can't limit number of results when using distinct. Exemple :
$stores = $this->dm->createQueryBuilder('Application\Document\Item')
->distinct('storeName')
->limit(10)
->getQuery()
->execute();
This query render 100 entries but I want only 10 results.
With query builder class in ORM you need to use:
->setMaxResults(10);
As per #Siol and #john Smith said, in ODM you could use limit:
->limit(10);
I don't think distinct will work with limit as suggested in the Jira mongodb issue ticket Ability to use Limit() with Distinct():
The current Distinct() implementation only allows for bringing back
ALL distinct values in the collection or matching a query, but there
is no way to limit these results. This would be very convenient and
there are many use cases.
I'm using luamongo to query mongodb. I'm quite inexperienced with mongodb, and I'm having trouble figuring out how to specify the sorting/order for the query. I don't see anything specifically about sorting on the project's wiki, but I might be missing something.
Is there a way to do this, or do I need to manually sort the returned results?
Thanks!
From https://github.com/moai/luamongo/issues/14:
To sort a query: mongodb:query("database.collection", {query = {field=value}, orderby = {field = 1}})
I don't know if I am doing something wrong or it is a bug.
I have the following code:
Query criteria = new Query(Criteria.where("locationTime").gte(
"date-time"));
criteria.fields().exclude("friends");
NearQuery query = NearQuery.near(point).maxDistance(maxDistance)
.num(limit).query(criteria);
GeoResults<Profile> result = mongoTemplate
.geoNear(query, Profile.class);
I am executing the query and profiles near by retrieved correctly according to distance and the "locationTime" criteria but it seems to ignore the excluded field and retrieving the profiles with their friends.
When I use simple query the exclude/include fields works perfectly.
I looked every where and could not find any resemble use-case, please let me know if i am doing something wrong.
Thanks.
There's no way to limit the fields with a geoNear command, as far as I know.
I looked into calling executeCommand to try to work around the limitations of Spring Data, but it looks like they don't even have a way to do it from the raw command.