类似于用Mongo在数组中查询对象中的字段？询问者想要查询对象中的特定字段，但我想要的与他相反。
我的数据
{ "_id": "ffb76dea811a6773c9481fd35262fe7f",
"fieldA" : "A",
"fieldB" : "B",
"fieldC" : [
{ "group1" : "100", "group2" : "200", "id" : "b0a05edd3cb0d35674174f34da1b3021"},
{ "group1" : "110", "group2" : "230", "id" : "b9071b34c21f948e69cb39df7dbf10a7"}
]
}
如何查询获取
{
"fieldA" : "A",
"fieldC" : [
{ "group1" : "100", "group2" : "200" },
{ "group1" : "110", "group2" : "230" }
]
}
关键点是我不希望id出现在我的查询结果中
db.test.insertOne({"_id":"ffb76dea811a6773c9481fd35262fe7f","fieldA":"A","fieldB":"B","fieldC":[{"group1":"100","group2":"200","id":"b0a05edd3cb0d35674174f34da1b3021"},{"group1":"110","group2":"230","id":"b9071b34c21f948e69cb39df7dbf10a7"}]})
mongoDB中find的第二个参数是投影选项，用于从结果中包含或排除字段。在您的情况下，您需要按如下方式使用它：
db.test.find({},{"fieldC.id":0, fieldB: 0, "_id":0})
请参阅此处了解投影的工作原理https://docs.mongodb.com/manual/reference/method/db.collection.find/
