mongodb aggregation match multiple $and on the same field - mongodb

Question

i have a document like this :
{
"ExtraFields" : [
{
"value" : "print",
"fieldID" : ObjectId("5535627631efa0843554b0ea")
},
{
"value" : "14",
"fieldID" : ObjectId("5535627631efa0843554b0eb")
},
{
"value" : "POLYE",
"fieldID" : ObjectId("5535627631efa0843554b0ec")
},
{
"value" : "30",
"fieldID" : ObjectId("5535627631efa0843554b0ed")
},
{
"value" : "0",
"fieldID" : ObjectId("5535627631efa0843554b0ee")
},
{
"value" : "0",
"fieldID" : ObjectId("5535627731efa0843554b0ef")
},
{
"value" : "0",
"fieldID" : ObjectId("5535627831efa0843554b0f0")
},
{
"value" : "42",
"fieldID" : ObjectId("5535627831efa0843554b0f1")
},
{
"value" : "30",
"fieldID" : ObjectId("5535627831efa0843554b0f2")
},
{
"value" : "14",
"fieldID" : ObjectId("5535627831efa0843554b0f3")
},
{
"value" : "19",
"fieldID" : ObjectId("5535627831efa0843554b0f4")
}
],
"id" : ObjectId("55369e60733e4914550832d0"), "title" : "A product"
}
what i want is to match one or more sets from the ExtraFields array. For example, all the products that contain the values print and 30. Since a value may be found in more than one fieldID (like 0 or true) we need to create a set like
WHERE (fieldID : ObjectId("5535627631efa0843554b0ea"), value : "print")
Where i'm having problems is when querying more than one fields. The pipeline i came up with is :
db.products.aggregate([
{'$unwind': '$ExtraFields'},
{
'$match': {
'$and': [{
'$and': [{'ExtraFields.value': {'$in': ["A52A2A"]}}, {
'ExtraFields.fieldID': ObjectId("5535627631efa0843554b0ea")
}]
}
,
{
'$and': [{'ExtraFields.value': '14'}, {'ExtraFields.fieldID': ObjectId("5535627631efa0843554b0eb")}]
}
]
}
},
]);
This returns zero results, but this is what i want to do in theory. Match all items that contain set 1 AND all that contain set 2.
The end result should look like a faceted search output :
[
{
"_id" : {
"values" : "18",
"fieldID" : ObjectId("5535627831efa0843554b0f3")
},
"count" : 2
},
{
"_id" : {
"values" : "33",
"fieldID" : ObjectId("5535627831efa0843554b0f2")
},
"count" : 1
}
]
Any ideas?

Answer 1

You could try the following aggregation pipeline
db.products.aggregate([
{
"$match": {
"ExtraFields.value": { "$in": ["A52A2A", "14"] },
"ExtraFields.fieldID": {
"$in": [
ObjectId("5535627631efa0843554b0ea"),
ObjectId("5535627631efa0843554b0eb")
]
}
}
},
{
"$unwind": "$ExtraFields"
},
{
"$match": {
"ExtraFields.value": { "$in": ["A52A2A", "14"] },
"ExtraFields.fieldID": {
"$in": [
ObjectId("5535627631efa0843554b0ea"),
ObjectId("5535627631efa0843554b0eb")
]
}
}
},
{
"$group": {
"_id": {
"value": "$ExtraFields.value",
"fieldID": "$ExtraFields.fieldID"
},
"count": {
"$sum": 1
}
}
}
])
With the sample document provided, this gives the output:
/* 1 */
{
"result" : [
{
"_id" : {
"value" : "14",
"fieldID" : ObjectId("5535627631efa0843554b0eb")
},
"count" : 1
}
],
"ok" : 1
}