MongoDB 查询，以匹配包含数组字段的文档
要匹配包含数组字段的文档，请使用$elemMatch运算符。让我们创建一个包含文档的集合-
> db.demo592.insertOne(
... {
... "id":101,
... "details" : [
... { "Name" : "Chris", "Value" : "200"},
... {"Name" : "David", "Value" : "800"}
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e930d8ffd2d90c177b5bcd6")
}
> db.demo592.insertOne(
... {
... id:102,
... "details" : [
... { "Name" : "Chris", "Value" : "500"},
... {"Name" : "David", "Value" : "900"}
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e930d90fd2d90c177b5bcd7")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo592.find();
这将产生以下输出-
{ "_id" : ObjectId("5e930d8ffd2d90c177b5bcd6"), "id" : 101, "details" : [
{ "Name" : "Chris", "Value" : "200" },
{ "Name" : "David", "Value" : "800" }
] }
{ "_id" : ObjectId("5e930d90fd2d90c177b5bcd7"), "id" : 102, "details" : [
{ "Name" : "Chris", "Value" : "500" },
{ "Name" : "David", "Value" : "900" }
] }以下是要匹配的查询-
> db.demo592.find(
... {
... "$and" : [
... { "details" : { "$elemMatch" : { "Name" : "Chris", "Value" : { "$gte" : "500" } } } },
... { "details" : { "$elemMatch" : { "Name" : "David", "Value" : { "$gte" : "600" } } } }
... ]
... }
... );这将产生以下输出-
{ "_id" : ObjectId("5e930d90fd2d90c177b5bcd7"), "id" : 102, "details" : [
{ "Name" : "Chris", "Value" : "500" }, { "Name" : "David", "Value" : "900" }
] }