MongoDB中按多个条件查询嵌套数组
要查询嵌套数组，请在MongoDB中使用$elemMatch。让我们创建一个包含文档的集合-
> db.demo203.insertOne({
... "_id" : "101",
... "Name" : "Chris",
... "details1" : [
... {
... "empName" : "David",
... "salary" : "50000",
... "technology" : [
... "MySQL",
... "MongoDB"
... ]
... },
... {
... "empName" : "Carol",
... "salary" : "70000",
...
... "technology" : [
... "Java",
... "Spring"
... ]
... }
... ]
...}
...);
{ "acknowledged" : true, "insertedId" : "101" }在find()方法的帮助下显示集合中的所有文档-
> db.demo203.find();
这将产生以下输出-
{
"_id" : "101", "Name" : "Chris", "details1" : [
{ "empName" : "David", "salary" : "50000", "technology" : [ "MySQL", "MongoDB" ] },
{ "empName" : "Carol", "salary" : "70000", "technology" : [ "Java", "Spring" ] } ]
}这是通过多个条件查询嵌套数组的方法-
> db.demo203.find(
... {details1: { $elemMatch:{"technology" : "MySQL", "empName":"David"}}}
... ).pretty()这将产生以下输出-
{
"_id" : "101",
"Name" : "Chris",
"details1" : [
{
"empName" : "David",
"salary" : "50000",
"technology" : [
"MySQL",
"MongoDB"
]
},
{
"empName" : "Carol",
"salary" : "70000",
"technology" : [
"Java",
"Spring"
]
}
]
}