MongoDB查询以将文档的交集与字段相匹配
为此，请使用aggregate()。首先让我们创建一个包含文档的集合-
> db.demo393.insertOne(
... {
... Id1: "1",
... Name: "Chris",
... Id2: "100"
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e5e6dd522064be7ab44e804")
}
> db.demo393.insertOne(
... {
... Id1: "1",
... Name: "Chris",
... Id2: "101"
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e5e6dd522064be7ab44e805")
}
> db.demo393.insertOne(
... {
... Id1: "3",
... Name: "Chris",
... Id2: "100"
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e5e6dd522064be7ab44e806")
}
> db.demo393.insertOne(
... {
... Id1: "3",
... Name: "Mike",
... Id2: "101"
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e5e6dd522064be7ab44e807")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo393.find();
这将产生以下输出-
{ "_id" : ObjectId("5e5e6dd522064be7ab44e804"), "Id1" : "1", "Name" : "Chris", "Id2" : "100" }
{ "_id" : ObjectId("5e5e6dd522064be7ab44e805"), "Id1" : "1", "Name" : "Chris", "Id2" : "101" }
{ "_id" : ObjectId("5e5e6dd522064be7ab44e806"), "Id1" : "3", "Name" : "Chris", "Id2" : "100" }
{ "_id" : ObjectId("5e5e6dd522064be7ab44e807"), "Id1" : "3", "Name" : "Mike", "Id2" : "101" }以下是将文档的交集与字段相匹配的查询-
> db.demo393.aggregate([
... { "$match": { "Name": "Chris" } },
... { "$group": {
... "_id": "$Id1",
... "docs": { "$push": "$$ROOT" },
... "count": { "$sum": 1 }
... }},
... { "$match": {
... "count": { "$gt": 1 },
... "docs": {
... "$all": [
... { "$elemMatch": { "Id2": "100" } },
... { "$elemMatch": { "Id2": "101" } }
... ]
... }
... }}
... ])这将产生以下输出-
{ "_id" : "1", "docs" : [ { "_id" : ObjectId("5e5e6dd522064be7ab44e804"), "Id1" : "1", "Name" : "Chris", "Id2" : "100" }, { "_id" : ObjectId("5e5e6dd522064be7ab44e805"), "Id1" : "1", "Name" : "Chris", "Id2" : "101" } ], "count" : 2 }