Group and count distinct occurrences - mongodb

Question

I am trying to derive a query to get a count of distinct values and display the relevant fields. The grouping is done by the tempId and the date where the tempId can occur one-to-many times within a single day and within a time frame.
following is my approach,
db.getCollection('targetCollection').aggregate(
{
$match:{
"user.vendor": 'vendor1',
tool: "tool1",
date: {
"$gte": ISODate("2016-04-01"),
"$lt": ISODate("2016-04-04")
}
}
},
{
$group:{
_id: {
tempId: '$tempId',
month: { $month: "$date" },
day: { $dayOfMonth: "$date" },
year: { $year: "$date" }
},
count: {$sum : 1}
}
},
{
$group:{
_id: 1,
count: {$sum : 1}
}
})
This query generates the following output,
{
"_id" : 1,
"count" : 107
}
Which is correct but, I would like to show them separated by the date and with the particular count for that date. For example something like this,
{
"date" : 2016-04-01
"count" : 50
},
{
"date" : 2016-04-02
"count" : 30
},
{
"date" : 2016-04-03
"count" : 27
}
P.S. I am not sure how to put this question together as I am quite new to this technology. Please let me know if refinements are required in the question.
Following is the sample data of the mongodb collection that I am trying to query,
{
"_id" : 1,
"tempId" : "temp1",
"user" : {
"_id" : "user1",
"email" : "user1#email.com",
"vendor" : "vendor1"
},
"tool" : "tool1",
"date" : ISODate("2016-03-09T08:30:42.403Z")
},...

Answer 1

I have come up with the solution myself. What i did was,
I first grouped by the tempId and the date
Then I grouped by the date
This printed out the daily distinct count of tempId, the result I want. The query is as follows,
db.getCollection('targetCollection').aggregate(
{
$match:{
"user.vendor": 'vendor1',
tool: "tool1",
date: {
"$gte": ISODate("2016-04-01"),
"$lt": ISODate("2016-04-13")
}
}
},
{
$group:{
_id: {
tempId: "$tempId",
month: { $month: "$date" },
day: { $dayOfMonth: "$date" },
year: { $year: "$date" }
},
count: {$sum : 1}
}
},
{
$group:{
_id: {
month:"$_id.month" ,
day: "$_id.day" ,
year: "$_id.year"
},
count: {$sum : 1}
}
})

Answer 2

group them via date
db.getCollection('targetCollection').aggregate([
{
$match:{
"user.vendor": 'vendor1',
tool: "tool1",
date: {
"$gte": ISODate("2016-04-01"),
"$lt": ISODate("2016-04-04")
}
}
},
{
$group: {
_id: {
date: "$date",
tempId: "$tempId"
},
count: { $sum: 1 }
}
}
]);