MongoDB 通过多个数组项查找？

您可以使用 $all 运算符按多个数组项查找。为了理解这个概念，让我们用文档创建一个集合。

使用文档创建集合的查询如下 -

> db.findByMultipleArrayDemo.insertOne({"StudentFirstName":"John","StudentLastName":"Smith",
   "StudentCoreSubject":["Compiler","Operating System","Computer Networks"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c7ef07b559dd2396bcfbfc4")
}
> db.findByMultipleArrayDemo.insertOne({"StudentFirstName":"Carol","StudentLastName":"Taylor",
   "StudentCoreSubject":["MongoDB","MySQL","SQL Server"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c7ef09d559dd2396bcfbfc5")
}
> db.findByMultipleArrayDemo.insertOne({"StudentFirstName":"Bob","StudentLastName":"Taylor",
   "StudentCoreSubject":["MongoDB","MySQL","SQL Server"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c7ef0c7559dd2396bcfbfc6")
}
> db.findByMultipleArrayDemo.insertOne({"StudentFirstName":"David","StudentLastName":"Johnson",
   "StudentCoreSubject":["Compiler","Operating System","Computer Networks"]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c7ef0f2559dd2396bcfbfc7")
}

在find()方法的帮助下显示集合中的所有文档。查询如下 -

> db.findByMultipleArrayDemo.find().pretty();

以下是输出 -

{
   "_id" : ObjectId("5c7ef07b559dd2396bcfbfc4"),
   "StudentFirstName" : "John",
   "StudentLastName" : "Smith",
   "StudentCoreSubject" : [
      "Compiler",
      "Operating System",
      "Computer Networks"
   ]
}
{
   "_id" : ObjectId("5c7ef09d559dd2396bcfbfc5"),
   "StudentFirstName" : "Carol",
   "StudentLastName" : "Taylor",
   "StudentCoreSubject" : [
      "MongoDB",
      "MySQL",
      "SQL Server"
   ]
}
{
   "_id" : ObjectId("5c7ef0c7559dd2396bcfbfc6"),
   "StudentFirstName" : "Bob",
   "StudentLastName" : "Taylor",
   "StudentCoreSubject" : [
      "MongoDB",
      "MySQL",
      "SQL Server"
   ]
}
{
   "_id" : ObjectId("5c7ef0f2559dd2396bcfbfc7"),
   "StudentFirstName" : "David",
   "StudentLastName" : "Johnson",
   "StudentCoreSubject" : [
      "Compiler",
      "Operating System",
      "Computer Networks"
   ]
}

这是通过多个数组项查找的查询 -

> db.findByMultipleArrayDemo.find({ StudentCoreSubject: { $all: ["Compiler", "Computer Networks"] }}).pretty();

以下是带有数组项“编译器”和“计算机网络”的输出显示记录 -

{
   "_id" : ObjectId("5c7ef07b559dd2396bcfbfc4"),
   "StudentFirstName" : "John",
   "StudentLastName" : "Smith",
   "StudentCoreSubject" : [
      "Compiler",
      "Operating System",
      "Computer Networks"
   ]
}
{
   "_id" : ObjectId("5c7ef0f2559dd2396bcfbfc7"),
   "StudentFirstName" : "David",
   "StudentLastName" : "Johnson",
   "StudentCoreSubject" : [
      "Compiler",
      "Operating System",
      "Computer Networks"
   ]
}