我有一个非常简单的查询,但不能让它工作。 我有一个名为users的集合,其中包含uid字段。 我想从中获取uid字段的最大值。 以下是我的工作: -
var options = { "sort": [['uid',-1]] };
db.users.findOne({}, options , function(err, doc) {
console.log("Returned #" + doc.uid + " documents");
});
但这给了我99,而我的价值高达300。 我猜它匹配每个元素9然后比较它。 正确的答案应该是314
以下是条目在集合中的保存方式: -
{
{
_id: "531181a3ec9af9107d2b4ccd",
age: "0",
carModel: "bullet motorcycle",
chargePrice: "",
contact: "",
email: "",
fbid: "1179803227",
fromLat: "28.4594965",
fromLon: "77.0266383",
fromName: "Gurgaon, Haryana, India",
fuelType: "Petrol",
id: "215",
image: "http://graph.facebook.com/1179803227/picture?type=large",
name: "Sandeep Yadav",
points: "0",
regid: "abc",
returnTime: "15:41 Hrs",
sex: "0",
smoking: "No Smoking allowed",
startTime: "15:41 Hrs",
toLat: "28.510782",
toLon: "77.048646",
toName: "Sector 23 ,HUDA Market, Huda, Sector 23, Gurgaon, Haryana, India",
uid: 311
},
{
_id: "531181a3ec9af9107d2b4cce",
age: "0",
carModel: "2014 Nissan sentra",
chargePrice: "USD 30",
contact: "",
email: "",
fbid: "100001451156666",
fromLat: "27.950575",
fromLon: "-82.4571776",
fromName: "Tampa, FL, United States",
fuelType: "Petrol",
id: "214",
image: "http://graph.facebook.com/100001451156666/picture?type=large",
name: "Kelly J. Dugan",
points: "0",
regid: "abc",
returnTime: "23:04 Hrs",
sex: "0",
smoking: "Doesnt Matter",
startTime: "16:02 Hrs",
toLat: "25.7889689",
toLon: "-80.2264393",
toName: "Miami, FL, United States",
uid: 308
}
}
答案 0 :(得分:1)
试试这个:
db.users.find({}).sort("uid":-1).limit(1)
将找到所有用户,然后对它们进行排序,然后返回第一个用户。