MongoDB查询以转换字段值并在投影过程中创建日期的日期时间？
要将字段值转换为创建日期时间，请使用MongoDBaggregate()。让我们创建一个包含文档的集合-
> db.demo209.insertOne(
... {
... "_id" : "101",
... "details" : [
... {
... "dat" : 1528929908,
... "Name" : "Chris"
... },
... {
... "dat" : 1529082069,
... "Name":"Carol"
... }
... ],
... "Age" : 25,
... "CountryName" : "US"
... }
...);
{ "acknowledged" : true, "insertedId" : "101" }在find()方法的帮助下显示集合中的所有文档-
> db.demo209.find().pretty();
这将产生以下输出-
{
"_id" : "101",
"details" : [
{
"dat" : 1528929908,
"Name" : "Chris"
},
{
"dat" : 1529082069,
"Name" : "Carol"
}
],
"Age" : 25,
"CountryName" : "US"
}以下是转换字段值并在投影期间创建日期时间的查询-
> db.demo209.aggregate({
... "$unwind": "$details"
... }, {
... "$project": {
... "Age": 1,
... "CountryName": 1,
... "Name": "$details.Name",
... "DayOfMonth": {
... "$dayOfMonth": {
... "$add": [new Date(0), {
... "$multiply": ["$details.dat", 1000]
... }]
... }
... }
... }
...})这将产生以下输出-
{ "_id" : "101", "Age" : 25, "CountryName" : "US", "Name" : "Chris", "DayOfMonth" : 13 }
{ "_id" : "101", "Age" : 25, "CountryName" : "US", "Name" : "Carol", "DayOfMonth" : 15 }