如何在MongoDB中的阵列上执行AND查询？
要获得与MongoDB中的AND类似的结果，请使用$all运算符。首先让我们创建一个包含文档的集合-
> db.andQueryDemo.insertOne({"StudentName":"Carol Taylor","FavouriteSubject":["C","Java","MongoDB","MySQL"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc73e7a8f9e6ff3eb0ce433")
}
> db.andQueryDemo.insertOne({"StudentName":"David Miller","FavouriteSubject":["C++","Java","MongoDB","SQL Server"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc73ea48f9e6ff3eb0ce434")
}
> db.andQueryDemo.insertOne({"StudentName":"Carol Taylor","FavouriteSubject":["Python","PL/SQL"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc73ed38f9e6ff3eb0ce435")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.andQueryDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cc73e7a8f9e6ff3eb0ce433"),
"StudentName" : "Carol Taylor",
"FavouriteSubject" : [
"C",
"Java",
"MongoDB",
"MySQL"
]
}
{
"_id" : ObjectId("5cc73ea48f9e6ff3eb0ce434"),
"StudentName" : "David Miller",
"FavouriteSubject" : [
"C++",
"Java",
"MongoDB",
"SQL Server"
]
}
{
"_id" : ObjectId("5cc73ed38f9e6ff3eb0ce435"),
"StudentName" : "Carol Taylor",
"FavouriteSubject" : [
"Python",
"PL/SQL"
]
}以下是使用$all在MongoDB中的数组上执行AND查询的查询。在这里，我们显示同时包含“Java”和“MongoDB”作为FavouriteSubject的数组-
> db.andQueryDemo.find({FavouriteSubject:{$all:["Java","MongoDB"]}}).pretty();这将产生以下输出-
{
"_id" : ObjectId("5cc73e7a8f9e6ff3eb0ce433"),
"StudentName" : "Carol Taylor",
"FavouriteSubject" : [
"C",
"Java",
"MongoDB",
"MySQL"
]
}
{
"_id" : ObjectId("5cc73ea48f9e6ff3eb0ce434"),
"StudentName" : "David Miller",
"FavouriteSubject" : [
"C++",
"Java",
"MongoDB",
"SQL Server"
]
}