MongoDB逆查询返回除特定文档之外的所有项目？
要获取除某些特定文档以外的文档，请使用$nor和$and。首先让我们创建一个包含文档的集合-
> db.demo1.insertOne({"StudentName":"Chris","StudentMarks":38});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e08a4f025ddae1f53b62216")
}
> db.demo1.insertOne({"StudentName":"David","StudentMarks":78});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e08a4f725ddae1f53b62217")
}
> db.demo1.insertOne({"StudentName":"Mike","StudentMarks":96});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e08a4fd25ddae1f53b62218")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.demo1.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5e08a4f025ddae1f53b62216"),
"StudentName" : "Chris",
"StudentMarks" : 38
}
{
"_id" : ObjectId("5e08a4f725ddae1f53b62217"),
"StudentName" : "David",
"StudentMarks" : 78
}
{
"_id" : ObjectId("5e08a4fd25ddae1f53b62218"),
"StudentName" : "Mike",
"StudentMarks" : 96
}这是获取查询逆的查询-
> db.demo1.find({$nor:[{$and:[{'StudentName':'David'},{'StudentMarks':78}]}]});这将产生以下输出。结果显示带有78以外的分数的学生记录-
{ "_id" : ObjectId("5e08a4f025ddae1f53b62216"), "StudentName" : "Chris", "StudentMarks" : 38 }
{ "_id" : ObjectId("5e08a4fd25ddae1f53b62218"), "StudentName" : "Mike", "StudentMarks" : 96 }