按MongoDB集合中的日期分组？
要按日期分组，请在MongoDB聚合中使用$group。让我们创建一个包含文档的集合-
> db.demo657.insertOne({
... id: 1,
... Name: "Chris",
... DueDate: new ISODate("2020-04-22")
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea064b44deddd72997713d6")
}
> db.demo657.insertOne(
... {
... id: 1,
... Name: "John",
... DueDate: new ISODate("2020-04-22")
... }
...);
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea064b44deddd72997713d7")
}
> db.demo657.insertOne(
... {
... id: 1,
... Name: "Chris",
... DueDate: new ISODate("2020-04-22")
... }
...);
{
"acknowledged" : true,
"insertedId" : ObjectId("5ea064b44deddd72997713d8")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo657.find();
这将产生以下输出-
{ "_id" : ObjectId("5ea064b44deddd72997713d6"), "id" : 1, "Name" : "Chris", "DueDate" : ISODate("2020-04-22T00:00:00Z") }
{ "_id" : ObjectId("5ea064b44deddd72997713d7"), "id" : 1, "Name" : "John", "DueDate" : ISODate("2020-04-22T00:00:00Z") }
{ "_id" : ObjectId("5ea064b44deddd72997713d8"), "id" : 1, "Name" : "Chris", "DueDate" : ISODate("2020-04-22T00:00:00Z") }以下是按日期对MongoDB集合中的日期进行分组的查询-
> db.demo657.aggregate([
... {$match: {id:1, DueDate: {$gte:new ISODate('2020-04-21'), $lt:new ISODate ("2020-04-23")}}},
... {$project:
... {day: {'$dayOfMonth': '$DueDate'},month: {'$month':'$DueDate'},year: {'$year':'$DueDate'},Name:"$Name" }
... },
... {$group: {
... _id: {day:'$day',month:'$month',year:'$year'},
... ListOfNames: {$push:{Name:'$Name'}}
... }}
... ])这将产生以下输出-
{ "_id" : { "day" : 22, "month" : 4, "year" : 2020 }, "ListOfNames" : [ { "Name" : "Chris" }, { "Name" : "John" }, { "Name" : "Chris" } ] }