从MongoDB中的查找查询中检索数组值？
若要检索数组值，请使用点（。）表示法。首先让我们创建一个包含文档的集合-
> db.retrievingArrayDemo.insertOne(
{ "UserDetails" : [
{ "UserName" : "John", "UserAge" : 23 } ],
"UserCountryName" : "AUS",
"UserLoginDate" : new ISODate(),
"UserMessage" : "Hello"
}
);
{
"acknowledged" : true,
"insertedId" : ObjectId("5ce9718478f00858fb12e920")
}
> db.retrievingArrayDemo.insertOne(
{ "UserDetails" : [
{ "UserName" : "Sam", "UserAge" : 24 } ],
"UserCountryName" : "UK",
"UserLoginDate" : new ISODate(),
"UserMessage" : "Bye"
}
);
{
"acknowledged" : true,
"insertedId" : ObjectId("5ce9718478f00858fb12e921")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.retrievingArrayDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5ce9718478f00858fb12e920"),
"UserDetails" : [
{
"UserName" : "John",
"UserAge" : 23
}
],
"UserCountryName" : "AUS",
"UserLoginDate" : ISODate("2019-05-25T16:47:00.211Z"),
"UserMessage" : "Hello"
}
{
"_id" : ObjectId("5ce9718478f00858fb12e921"),
"UserDetails" : [
{
"UserName" : "Sam",
"UserAge" : 24
}
],
"UserCountryName" : "UK",
"UserLoginDate" : ISODate("2019-05-25T16:47:00.670Z"),
"UserMessage" : "Bye"
}以下是从查找查询中检索数组值的查询-
> db.retrievingArrayDemo.find({"UserCountryName" : "UK", "UserDetails.UserName":"Sam"}).pretty();这将产生以下输出-
{
"_id" : ObjectId("5ce9718478f00858fb12e921"),
"UserDetails" : [
{
"UserName" : "Sam",
"UserAge" : 24
}
],
"UserCountryName" : "UK",
"UserLoginDate" : ISODate("2019-05-25T16:47:00.670Z"),
"UserMessage" : "Bye"
}