Line chart from date picker
- Philipp Marbach
This aggregation creates a line chart from the date picker in a data collection.
Result:
Code
Group #1
{
"_id": {
"month": {
"$month": "$answers.date"
},
"year": {
"$year": "$answers.date"
}
},
"count": {
"$sum": "$answers.totalnumberofParticipants"
}
}Sort
{
"_id.year": 1,
"_id.month": 1
}Group #2
{
"_id": "$result",
"events": {
"$push": {
"x": {
"$concat": [
{
"$toString": "$_id.month"
},
"-",
{
"$toString": "$_id.year"
}
]
},
"y": "$count"
}
}
}Project
Unwind
ReplaceRoot
Explanation
Grouping by Month and Year:
The data is grouped based on the month and year of the "answers.date" field.
The "$group" stage groups the data using the "$month" and "$year" operators.
The grouped data will have an "_id" field containing the month and year information, and a "count" field representing the sum of "answers.totalnumberofParticipants" within each group.
Sorting by Year and Month:
The "$sort" stage sorts the grouped data based on the "_id.year" field in ascending order, followed by the "_id.month" field in ascending order.
Grouping by Result and Creating Events:
The data is grouped again, this time using the "result" field.
The "$push" operator creates an array of "events" containing the "x" and "y" values.
The "x" value is a concatenation of the "_id.month" and "_id.year" fields, converted to strings.
The "y" value is the "count" field from the previous grouping.
Projecting the Result:
The "$project" stage specifies which fields to include in the output.
The "_id" field is excluded.
The "result" field is created as an array containing an object with "id" and "data" fields.
The "id" field is set to "Participants".
The "data" field is set to the "events" array created in the previous stage.
Unwinding the Result:
The "$unwind" stage flattens the "result" array, creating separate documents for each element.
Replacing the Root:
The "$replaceRoot" stage promotes the "result" field to become the new root of the document.