Mongodb: find documents with array field that contains more than one SAME specified value - mongodb

Question

There is three documents in collection test:
// document 1
{
"id": 1,
"score": [3,2,5,4,5]
}
// document 2
{
"id": 2,
"score": [5,5]
}
// document 3
{
"id": 3,
"score": [5,3,3]
}
I want to fetch documents that score field contains [5,5].
query:
db.test.find( {"score": {"$all": [5,5]}} )
will return document 1, 2 and 3, but I only want to fetch document 1 and 2.
How can I do this?

Answer 1

After reading your problem I personally think mongodb not supported yet this kind of query. If any one knows about how to find this using mongo query they defiantly post answers here.
But I think this will possible using mongo forEach method, so below code will match your criteria
db.collectionName.find().forEach(function(myDoc) {
var scoreCounts = {};
var arr = myDoc.score;
for (var i = 0; i < arr.length; i++) {
var num = arr[i];
scoreCounts[num] = scoreCounts[num] ? scoreCounts[num] + 1 : 1;
}
if (scoreCounts[5] >= 2) { //scoreCounts[5] this find occurrence of 5
printjsononeline(myDoc);
}
});

Answer 2

Changed in version 2.6.
The $all is equivalent to an $and operation of the specified values; i.e. the following statement:
{ tags: { $all: [ "ssl" , "security" ] } }
is equivalent to:
{ $and: [ { tags: "ssl" }, { tags: "security" } ] }
I think you need to pass in a nested array -
So try
db.test.find( {"score": {"$all": [[5,5]]}} )
Source
Changed in version 2.6.
When passed an array of a nested array (e.g. [ [ "A" ] ] ), $all can now match documents where the field contains the nested array as an element (e.g. field: [ [ "A" ], ... ]), or the field equals the nested array (e.g. field: [ "A" ]).
http://docs.mongodb.org/manual/reference/operator/query/all/

Answer 3

You can do it with an aggregation. The first step can use an index on { "score" : 1 } but the rest is hard work.
db.test.aggregate([
{ "$match" : { "score" : 5 } },
{ "$unwind" : "$score" },
{ "$match" : { "score" : 5 } },
{ "$group" : { "_id" : "$_id", "sz" : { "$sum" : 1 } } }, // use $first here to include other fields in the results
{ "$match" : { "sz" : { "$gte" : 2 } } }
])