[Mongo] group statistics time: aggregate, group, distinct, mongoaggregate

[Mongo] group statistics time: aggregate, group, distinct, mongoaggregate
Some records recorded by date in development require statistics in various dimensions, such as day, month, year, and hour ,.. For Grouping statistics, some fields need to be de-duplicated. In the previous [Mongo] grouping statistics by time (group time formatting), group is used to achieve day-by-day statistics, however, using the new Date () method may be a bit difficult. Today I have read about aggregate and used aggregation to write time statistics.

Tips.

The data structure is still:

/* 0 */{  "_id" : ObjectId("541fcc51c6c36038bc6b81cd"),  "url" : "http://wifi21.com/",  "addtime" : ISODate("2014-08-19T00:15:02Z")}/* 1 */{  "_id" : ObjectId("541fcc51c6c36038bc6b81ce"),  "url" : "http://meiwen.me/src/index.html",  "addtime" : ISODate("2014-08-19T00:15:07Z")}...

Collect pv values by month (equivalent to group)

db.msds_accessrecord.aggregate([    {$group: {        _id: {            "$month": "$addtime"        },      pv: {$sum: 1}}    },    {$sort: {"_id": 1}}]);

Statistical results

/* 0 */{    "result" : [         {            "_id" : 8,            "pv" : 583        },         {            "_id" : 9,            "pv" : 1399        }    ],    "ok" : 1}

Calculate the url value on a monthly basis and remove the duplicate url. Here is just a demonstration. The statistics may be meaningless (equivalent to group + distinct)

db.msds_accessrecord.aggregate([    {$group: {        _id: {            "month": {"$month": "$addtime"},            "url": "$url"        }    }},    {$group: {_id:"$_id.month", uv: {$sum: 1}}},    {$sort: {"_id":1}}]);

Pipelines, sorting, and aggregation are used here.

Statistical results

/* 0 */{    "result" : [         {            "_id" : 8,            "uv" : 41        },         {            "_id" : 9,            "uv" : 134        }    ],    "ok" : 1}

Reference:

Aggregate usage: http://docs.mongodb.org/manual/reference/method/db.collection.aggregate/#db.collection.aggregate

Date Aggregate functions: http://docs.mongodb.org/manual/reference/operator/aggregation-date/

This article is from the "orangleliu notebook" blog, please be sure to keep this http://blog.csdn.net/orangleliu/article/details/39932081

Mysql and mongo select count (distinct username) from log group by time

Db. log. group ({key: {time: 1}, cond: {}, reduce: function (curr, result) {if (result. arr. indexOf (curr. username) =-1) {result. arr. push (curr. username); result. count ++ ;}}, initial: {arr: [], count: 0 }});

Locally verified, the initial method initializes the variables of each group result. The reduce method traverses and executes the values of each group. Here, arr stores username to implement distinct, if not, insert and count in. I posted it from the console. There is no format. It's a bit messy... if you don't understand it, ask me again.