我正在try 为集合中的所有文件投影文件名和文件大小,大小为50 mb及以上,但我无法指定类型FileSize,因为它的类型为Int
我希望投影是
{
"result" : [
{
"_id" : ObjectId("5652c399a21dad0bb01b6308"),
"FileName" : "1234567890.xml",
"FileSize" : "11.06 MB"
},
{
"_id" : ObjectId("5652c399a21dad0bb01b630f"),
"FileName" : "2468101214.xml",
"FileSize" : "320.48 MB"
},
{
"_id" : ObjectId("5652c399a21dad0bb01b631f"),
"FileName" : "3691215180.xml",
"FileSize" : "12.95 MB"
}
}
但到目前为止,我只能返回以下内容
{
"result" : [
{
"_id" : ObjectId("5652c399a21dad0bb01b6308"),
"FileName" : "1234567890.xml",
"FileSize" : 11.0610504150390630
},
{
"_id" : ObjectId("5652c399a21dad0bb01b630f"),
"FileName" : "2468101214.xml",
"FileSize" : 320.4827098846435500
},
{
"_id" : ObjectId("5652c399a21dad0bb01b631f"),
"FileName" : "3691215180.xml",
"FileSize" : 12.9519605636596680
}
}
我的问题是:
db.MyCollection.aggregate(
// Pipeline
[
// Stage 1
{
$match: {
FileSize: {$gte: 5000000}
}
},
// Stage 2
{
$project: {
FileName: 1,
FileSize: {$divide: ["$FileSize", 1048576]}
}
},
// Stage 3
{
$project:{
FileName:1,
FileSize:{$concat:["$FileSize", "MB"]}
}
}
如何定义文件大小和"MB"字段?