Mongodb聚合 时间分组
查询collection中,按天分组,每天的数据数量,并按照数量count倒序
// Requires official MongoShell 3.6+
use MediaNetDB;
db.getCollection("TestCollection").aggregate(
[
{
"$project" : {
"Day" : {
"$dateToString" : {
"format" : "%Y-%m-%d",
"date" : "$AddDateTime"
}
},
"Time" : {
"$dateToString" : {
"format" : "%H:%M:%S:%L",
"date" : "$AddDateTime"
}
}
}
},
{
"$group" : {
"_id" : {
"Day" : "$Day"
},
"count" : {
"$sum" : 1.0
}
}
},
{
"$project" : {
"_id" : 0.0,
"Day" : "$_id.Day",
"Count" : "$count"
}
},
{
"$sort" : {
"Count" : -1.0
}
}
],
{
"allowDiskUse" : false
}
);