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"
]
}