I have an issue getting the sum of an array of objects, Document is mentioned below.
{
"orderNumber":123,
"items":[
{
"price":2
},
{
"price":10
}
]
}
I need the below document
{
"orderNumber":123,
"totalItemsValue":12,
"items":[
{
"price":2
},
{
"price":10
}
]
}
Sum of prices in totalItemsValue field.I need a solution in spring mongo data.I will be thankful.
There ae lot of ways, easiest way is given below. Spring data doesn't provide any operation for $addFields. So we do a Trick.
Autowire the mongoTemplate
@Autowired
private MongoTemplate mongoTemplate;
And the method is like
public List<Object> test() {
Aggregation aggregation = Aggregation.newAggregation(
a-> new Document("$addFields",
new Document("totalItemsValue",
new Document("$reduce"
new Document()
.append("input","$items")
.append("initialValue",0)
.append("in",
new Document("$add",Arrays.asList("$$value",1))
)
)
)
)
).withOptions(AggregationOptions.builder().allowDiskUse(Boolean.TRUE).build());
return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(YOUR_COLLECTION.class), Object.class).getMappedResults();
}
Working Mongo playground
