在MongoDB中编写等式而不使用$ eq运算符
让我们首先创建包含文档的集合-
> db.operatorDemo.insertOne({"StudentSubject":["MongoDB","MySQL","Java"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cef94eaef71edecf6a1f6a2")
}
> db.operatorDemo.insertOne({"StudentSubject":["Java","C","C++"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cef94faef71edecf6a1f6a3")
}在find()方法的帮助下显示集合中的所有文档-
> db.operatorDemo.find().pretty();
输出结果
{
"_id" : ObjectId("5cef94eaef71edecf6a1f6a2"),
"StudentSubject" : [
"MongoDB",
"MySQL",
"Java"
]
}
{
"_id" : ObjectId("5cef94faef71edecf6a1f6a3"),
"StudentSubject" : [
"Java",
"C",
"C++"
]
}以下是不带$eq运算符的相等查询：
> db.operatorDemo.find({StudentSubject:"MongoDB"});输出结果
{ "_id" : ObjectId("5cef94eaef71edecf6a1f6a2"), "StudentSubject" : [ "MongoDB", "MySQL", "Java" ] }