Database
[{
"_id": ObjectId("5ab3f0975c4f698c8a39ea22"),
"DISTRICT": "vskp",
"STATION": "appcb",
"TAKEN_DATE": ISODate("2018-02-25T00:18:00.000Z"),
"OZONE": 8.84,
"pm10": "69.0",
"pm2dots": "49.0",
"DATA_FROM": "vsk",
"CREATE_DATE": ISODate("2018-02-05T00:30:05.867Z")
}]
Query
db.collection.aggregate([{
$match: {
CREATE_DATE: {
$lte: ISODate("2018-03-23T00:18:00.000Z"),
$gte: ISODate("2017-12-23T00:18:00.000Z")
}
}
},
{
$group: {
_id: {
month: {
$month: "$CREATE_DATE"
},
year: {
$year: "$CREATE_DATE"
}
},
avgofozone: {
$avg: "$OZONE"
}
}
},
{
$sort: {
"year": -1
}
}, {
$project: {
year: "$_id.year",
month: "$_id.month",
_id: 0,
avgofozone: 1
}
}
])