How to use aggregation for MongoDB to filter based on $and/$or?

问题

I don't quite understand to use $or or $and operators with MongoDB.

Let's say I have following data:

{
    "_id" : "0211dd50-6283-11e6-be4b-01259186ebdc",
    "customer_id" : 75832,
    "prod_display_id" : "8c890b9c-7824-11e5-9cf1-24519096eb0c",
    "record_ids" : [
        ObjectId("1377ki5f8782b634fbf92b07b"),
        ObjectId("6283gf5f922b634fbf32b07a"),
        ObjectId("9913zd5f234b634fbf22b07c")
    ],
    "create_dt" : ISODate("2014-01-12T13:31:42.740Z")
}, 
{
    "_id" : "3454ke24-9372-11e6-be4b-01259186ebdc",
    "customer_id" : 75832,
    "prod_display_id" : "2d723b5c-8823-77y5-9cf1-00259096eb0c",
    "record_ids" : [
        ObjectId("1377ki5f8782b634fbf92b07b")
    ],
    "create_dt" : ISODate("2014-03-12T15:45:01.650Z")
}, 
{
    "_id" : "0211dd50-6283-23t6-it84-63957834kjhdd",
    "customer_id" : 11486,
    "prod_display_id" : "8c890b9c-7824-11e5-9cf1-00259096eb0c",
    "record_ids" : [
        ObjectId("9870kr5f9234b745fbf23g12b")
    ],
    "create_dt" : ISODate("2015-02-23T16:23:53.112Z")
}
....

Now, I would like to find all of the users that have certain record_id's. Lets say I want all users that have ObjectId(....) OR ObjectId(....) (that is, one or the other.)

I think the correct aggregation operator is:

> db.collection.aggregate([{ $project: { content_id : {$or : [ObjectId("...."), ObjectId("...")]}}}])

Similarly, the AND operation should be

> db.collection.aggregate([{ $project: { content_id : {$and : [ObjectId("...."), ObjectId("...")]}}}])

I am wrong however! If I run the above, both $project operations outputs all files, regardless whether the certain ObjectId() exists or not. What am I doing wrong?

回答1:

First of all you don't need aggregation for this; and you don't need the $or operator.

To find to find all "users" that have certain ObjectId in "record_ids" simply use the $in operator.

db.collection.find( { "record_ids": { "$all": <array of record_ids> } } )

To find to find all "users" that have all ObjectIds in "record_ids" simply use the $all operator

db.collection.find( { "record_ids": { "$in": <array of record_ids> } } )

回答2:

You don't require any aggregate to run such simple queries.

    db.collection.find({$or : [{"content_id":ObjectId("....")},{"content_id": ObjectId("...")} ] } )

OR

    db.collection.find({"content_id":{ "$in":[ObjectId("...."),ObjectId("....")] }  } )

https://docs.mongodb.org/v3.0/reference/operator/query/in/

来源：https://stackoverflow.com/questions/35019119/how-to-use-aggregation-for-mongodb-to-filter-based-on-and-or

标签

mongodb

mongodb-query

aggregation-framework