Question

这是我在MongoDB中的示例数据库

<title>{{ title_data }}</title>

我需要选择拥有超过3000个粉丝的用户名以及确认帐户的位置。这就是我想要做的事情：

{"userName":"John Smith", "followers":8075,"body":"my text 1","confirmed":"no"}
{"userName":"James Bond", "followers":819, "body":"my text 2", "confirmed":"yes"}
{"userName":"Julia Roberts","followers":3882,"body":"my text 3","confirmed":"yes"}
{"userName":"Matt Damon","followers":6531, "body":"my text 4","confirmed":"yes"}
{"userName":"Amy Adams","followers":3941, "body":"my text 5","confirmed":"no"}

但这种方式给了我完整的匹配线，而我只需要userName。能告诉你吗？

Answer 1

您必须指定返回字段;

db.collection.find( { $and:[{followers: { $gt: 3000 } }, {"confirmed" : "yes"}] }, {userName: 1, _id: 0})

可以找到更多详细信息here

此外，如果您要取消_id字段，则需要添加_id: 0。详情为here

Answer 2

你可以尝试

db.collection.find( { $and:[{followers: { $gt: 3000 } },  {"confirmed" : "yes"}] }).select({"userName":1})

Answer 3

使用

db.collection.find( { $and:[{followers: { $gt: 3000 } }, {"confirmed" : "yes"}] }, {"userName" :  1, _id : 0 })

仅从MongoDB中选择一个字段

3 个答案: