MongoDB查询多个文档字段上的完全匹配
为了精确匹配，请在MongoDB$in()中设置要匹配的值。首先让我们创建一个包含文档的集合-
> db.demo422.insertOne({"Name":"Chris","Marks":34});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e73a4059822da45b30346e1")
}
> db.demo422.insertOne({"Name":"Chris","Marks":56});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e73a40a9822da45b30346e2")
}
> db.demo422.insertOne({"Name":"David","Marks":78});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e73a4149822da45b30346e3")
}
> db.demo422.insertOne({"Name":"Sam","Marks":45});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e73a41e9822da45b30346e4")
}
> db.demo422.insertOne({"Name":"David","Marks":89});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e73a4239822da45b30346e5")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo422.find();
这将产生以下输出-
{ "_id" : ObjectId("5e73a4059822da45b30346e1"), "Name" : "Chris", "Marks" : 34 }
{ "_id" : ObjectId("5e73a40a9822da45b30346e2"), "Name" : "Chris", "Marks" : 56 }
{ "_id" : ObjectId("5e73a4149822da45b30346e3"), "Name" : "David", "Marks" : 78 }
{ "_id" : ObjectId("5e73a41e9822da45b30346e4"), "Name" : "Sam", "Marks" : 45 }
{ "_id" : ObjectId("5e73a4239822da45b30346e5"), "Name" : "David", "Marks" : 89 }以下是查询以获取与多个文档字段完全匹配的记录-
> db.demo422.find({'$and': [{'Name': {'$in': ['Chris', 'David']}, 'Marks': {'$in': [34,89]}}]});这将产生以下输出-
{ "_id" : ObjectId("5e73a4059822da45b30346e1"), "Name" : "Chris", "Marks" : 34 }
{ "_id" : ObjectId("5e73a4239822da45b30346e5"), "Name" : "David", "Marks" : 89 }