mongodb内嵌数组查询问题：如何限定返回与条件匹配的数组

//往数据库表“users”中插入测试数据> db.users.insertMany([{"_id" : NumberLong(1181675746),"shard_qty" : 4,"goods_qty" : 0,"shop_qty" : 0,"favorite_qty" : 4,"favorite_shards" : [ {"sid" : NumberLong(580),"favorite_dt" : ISODate("2015-06-26T12:13:06.405&＃43;08:00"),"is_attention" : true}, {"sid" : NumberLong(579),"favorite_dt" : ISODate("2015-06-26T12:13:06.405&＃43;08:00"),"is_attention" : true}, {"sid" : NumberLong(578),"favorite_dt" : ISODate("2015-06-26T12:13:06.405&＃43;08:00"),"is_attention" : true}, {"sid" : NumberLong(577),"favorite_dt" : ISODate("2015-06-26T13:20:48.449&＃43;08:00"),"is_attention" : true}]}]
)

//一&＃xff1a;假设查询条件为&＃xff1a;

> db.getCollection(&＃39;users&＃39;).findOne({&＃39;_id&＃39;:NumberLong(1181675746),&＃39;favorite_shards.sid&＃39;: {&＃39;$in&＃39;:[NumberLong(577),NumberLong(578)]}},{"favorite_shards":1}
)

//想要返回的数据&＃xff1a;

{"_id" : NumberLong(1181675746),"favorite_shards" : [ {"sid" : NumberLong(578),"favorite_dt" : ISODate("2015-06-26T12:13:06.405&＃43;08:00"),"is_attention" : true}, {"sid" : NumberLong(577),"favorite_dt" : ISODate("2015-06-26T13:20:48.449&＃43;08:00"),"is_attention" : true}]
}

//实际返回的数据&＃xff1a;

{"_id" : NumberLong(1181675746),"favorite_shards" : [{"sid" : NumberLong(580),"favorite_dt" : ISODate("2015-06-26T04:13:06.405Z"),"is_attention" : true},{"sid" : NumberLong(579),"favorite_dt" : ISODate("2015-06-26T04:13:06.405Z"),"is_attention" : true},{"sid" : NumberLong(578),"favorite_dt" : ISODate("2015-06-26T04:13:06.405Z"),"is_attention" : true},{"sid" : NumberLong(577),"favorite_dt" : ISODate("2015-06-26T05:20:48.449Z"),"is_attention" : true}]
}

//二&＃xff1a;正确的查询条件&＃xff1a;实现的逻辑就是将原来的数组拆开&＃xff0c;然后重组就好了。

> db.getCollection(&＃39;users&＃39;).aggregate([{"$match":{"_id":NumberLong(1181675746)}},{"$project":{"_id":1,"favorite_shards":1}},{"$unwind": "$favorite_shards"},{$match: {"favorite_shards.sid": {&＃39;$in&＃39;:[NumberLong(577),NumberLong(578)]}}},{"$group": {"_id": "$_id", "favorite_shards": {"$push": "$favorite_shards"}}}]).pretty()

{"_id" : NumberLong(1181675746),
"favorite_shards" : [{"sid" : NumberLong(578),"favorite_dt" : ISODate("2015-06-26T04:13:06.405Z"),"is_attention" : true},{"sid" : NumberLong(577),"favorite_dt" : ISODate("2015-06-26T05:20:48.449Z"),"is_attention" : true}
]
}