我有一个架构,它是这样的:
var photoSchema = new mongoose.Schema({
id: String, // Unique ID identifying this photo
file_name: String,
date_time: {type: Date, default: Date.now},
user_id: mongoose.Schema.Types.ObjectId, // The user id of the user who created the photo.
comments: [commentSchema] // Comment objects representing the comments made on this photo.
});
var Photo = mongoose.model('Photo', photoSchema);
我正在尝试查找具有最多评论的特定用户的照片。以下是我的操作过程:
Photo.aggregate([
{
$project: {
id: 1,
file_name: 1,
date_time: 1,
user_id: 1,
comments: 1,
length: {$size: "$comments"}
}
},
{
$match: {
user_id: mongoose.Schema.Types.ObjectId(request.params.id)
}
},
{
$sort: { length: -1 }
}
], function (err, info2){
if (err) {
// Query returned an error.
console.error('Doing /user/usage/:id error:', err);
response.status(400).send(JSON.stringify(err));
return;
}
console.log(info2);
finalOutput.most_commented = info2[0];
response.end(JSON.stringify(finalOutput));
});
控制台中只会得到一个空数组[],我知道$match没有起作用,因为如果我删除$match子句,它会给我整个表中具有最多评论的照片。我想根据用户ID过滤和获取属于特定用户的照片。
我不明白我做错了什么。
我尝试过:
1. $match: {user_id: mongoose.Schema.Types.ObjectId(request.params.id)}
2. $match: {user_id: request.params.id}
3. $match: {"user_id": request.params.id}