I can use the sum within the push operation in a MongoDB console. However, I am not getting how can I do the same using MongoTemplate?
$group : {
_id: "$some_id",
my_field: { $push : {$sum: "$my_field" }}
}
The code I am using for this is something like:
Aggregation aggregation =
Aggregation.newAggregation(
match(matchingCriteria),
group("some_id")
.count()
.as("count")
.push("my_field")
.as("my_field")
project("some_id", "count", "my_field"));
AggregationResults<MyModel> result =
mongoTemplate.aggregate(aggregation, "my_collection", MyModel.class);
The thing is I want the sum of my_field but it is coming as an array of my_field here(as I am directly using the push). I am able to achieve the same using the above sum inside of push operation. But not able to use that for MongoTemplate. My app is in Spring Boot. I have also looked into the docs for these methods but couldn't find much.
Also, I tried directly using .sum() as well on the field(without using the push), but that is not working for me as my_field is an inner object, and it's not a number but an array of numbers after the grouping. That is why I need to use the push and sum combination.
Any help regarding this is appreciated. Thanks in advance.
I was able to get this to work using the below code:
Aggregation aggregation =
Aggregation.newAggregation(
match(allTestMatchingCriteria),
project("some_id")
.and(AccumulatorOperators.Sum.sumOf("my_field"))
.as("my_field_sum")
group("some_id")
.count()
.as("count")
.push("my_field_sum")
.as("my_field_sum"),
project("some_id", "count", "my_field_sum"));
AggregationResults<MyModel> result =
mongoTemplate.aggregate(aggregation, "my_collection", MyModel.class);
I used AccumulatorOperators.Sum in the projection stage itself and sum the inner fields and get the desired output. Then I passed this to the grouping stage where I did the count aggregation as I needed that data as well and then had to project all the data generated to be collected as output.