MongoDB查询以从数组中的特定元素开始获取记录？
您可以将dot（。）表示法与数组索引一起使用，以获取从特定元素开始的记录。首先让我们创建一个包含文档的集合-
>db.arrayStartsWithElementDemo.insertOne({"PlayerName":"Chris","PlayerScore":[780,9000,456,789,987]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd29fed345990cee87fd889")
}
>db.arrayStartsWithElementDemo.insertOne({"PlayerName":"Robert","PlayerScore":[890,670,890,54646,42424]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd2a00c345990cee87fd88a")
}
>db.arrayStartsWithElementDemo.insertOne({"PlayerName":"David","PlayerScore":[909090,896555,3344433,78900]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd2a025345990cee87fd88b")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.arrayStartsWithElementDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cd29fed345990cee87fd889"),
"PlayerName" : "Chris",
"PlayerScore" : [
780,
9000,
456,
789,
987
]
}
{
"_id" : ObjectId("5cd2a00c345990cee87fd88a"),
"PlayerName" : "Robert",
"PlayerScore" : [
890,
670,
890,
54646,
42424
]
}
{
"_id" : ObjectId("5cd2a025345990cee87fd88b"),
"PlayerName" : "David",
"PlayerScore" : [
909090,
896555,
3344433,
78900
]
}以下是获取以特定元素890和670开始的数组的查询-
> db.arrayStartsWithElementDemo.find({"PlayerScore.0" : 890, "PlayerScore.1" : 670}).pretty();这将产生以下输出。这里，
{
"_id" : ObjectId("5cd2a00c345990cee87fd88a"),
"PlayerName" : "Robert",
"PlayerScore" : [
890,
670,
890,
54646,
42424
]
}