Python mongoengine在嵌套字段上获取值
我在mongodb中有以下列表Python mongoengine在嵌套字段上获取值,python,mongodb,mongoengine,Python,Mongodb,Mongoengine,我在mongodb中有以下列表 > db.article.find().pretty() { "_id" : ObjectId("5bebcfbb1b48d9974aac78ee"), "no" : 40, "subject" : "string", "content" : "string", "userid" : "string", "comments" : [ { "no" : 1,
> db.article.find().pretty()
{
"_id" : ObjectId("5bebcfbb1b48d9974aac78ee"),
"no" : 40,
"subject" : "string",
"content" : "string",
"userid" : "string",
"comments" : [
{
"no" : 1,
"content" : "First content",
"userid" : "john",
"parent" : null,
"seq" : 12,
"created_at" : ISODate("2018-11-14T16:33:01.943Z")
},
{
"no" : 2,
"content" : "Second",
"userid" : "doe",
"parent" : null,
"seq" : 25,
"created_at" : ISODate("2018-11-14T16:33:01.943Z")
},
}
现在我正在python应用程序中使用mongoengine
如果我想获取注释的no:2的seq
字段值(在这个代码中,它是25),我如何操作我的查询
我找到了与之相关的文档(),但我不知道它与我想要的完全相同
这里有什么解决办法吗
谢谢
db.getCollection('article').aggregate([
{"$project":{"comments.seq":1,"comments.no":1,"_id":0}},
{"$unwind":"$comments"},
{"$match":{"comments.no":NumberInt(2)}},
{"$project":{"comments.seq":1}}
])
你可以参考一下