Key examples of JavaScript querying the data in MongoDB by date

group by date aggregate query date statistics daily data (amount of information)
1

{ 
  "_id" : ObjectId("557ac1e2153c43c320393d9d"), 
  "msgType" : "text", 
  "sendTime" : ISODate("2015-06-12T11:26:26.000Z") 
} 

2

{ 
  "_id" : ObjectId("557ac1ee153c43c320393d9e"), 
  "msgType" : "text", 
  "sendTime" : ISODate("2015-06-12T11:26:38.000Z") 
} 

3

{ 
  "_id" : ObjectId("557ac2012de5d32d213963b5"), 
  "msgType" : "text", 
  "sendTime" : ISODate("2015-06-12T11:26:56.000Z") 
} 

4

{ 
  "_id" : ObjectId("557ac978bb31196e21d23868"), 
  "msgType" : "text", 
  "sendTime" : ISODate("2015-06-12T11:58:47.000Z") 
} 

5

{ 
  "_id" : ObjectId("557ac9afbb31196e21d23869"), 
  "msgType" : "text", 
  "sendTime" : ISODate("2015-06-12T11:59:43.000Z") 
} 

SQL Here

db.getCollection('wechat_message').aggregate( 
  [   
    {  $project : { day : {$substr: ["$sendTime", 0, 10] }}},     
    {  $group  : { _id : "$day", number : { $sum : 1 }}}, 
    {  $sort  : { _id : -1 }}     
  ] 
) 

Result Here

"result" : [  
    { 
      "_id" : "2015-07-06", 
      "number" : 13.0000000000000000 
    },  
    { 
      "_id" : "2015-07-05", 
      "number" : 3.0000000000000000 
    },  
    { 
      "_id" : "2015-07-03", 
      "number" : 10.0000000000000000 
    },  
    { 
      "_id" : "2015-07-02", 
      "number" : 29.0000000000000000 
    }, 
]

Three ways to query all information on a given day, based on the date
The mongodb query is really hard to understand. It takes a lot of effort to query a single day's information.

Method 1:

coll.aggregate([ 
     {$project:{sendDate: {$substr: ['$sendTime', 0, 10]}, sendTime: 1, content:1}}, 
     {$match:{sendDate: '2015-07-05'}}, 
    ]) 

Type 2 (variation of type 1) :

coll.aggregate([ 
     {$match: {'sendTime': {'$gte': new Date('2015-07-05'), '$lt': new Date('2015-07-06')}}} 

Mode 3 (variation of type 2) :

coll.aggregate([ 
     {$match: {'sendTime': {'$gte': new Date('2015-07-05 00:00:00'), '$lte': new Date('2015-07-05 23:59:59')}}} 

The query results are as follows (one way to show it: the others are slightly different) :

{ 
  "_id" : ObjectId("557ac1ee153c43c320393d9e"), 
  "msgType" : "text", 
  "sendTime" : ISODate("2015-06-12T11:26:38.000Z") 
} 

0