通过 Spring 引导存储库从 mongoDB 中的集合中获取最大日期

Question

I need to get the max date and the field "sendingSystemCode" need to be equal to '999' from collection in MongoDB (Compass) by Spring Boot repository.

For now I did it like that:

@Repository
public interface ControlFutureTransactionRepository extends 
MongoRepository<ControlFutureTransactionEntity, Integer>
{
    @Query("{'sendingSystemCode': {$eq: 999}}")
    List<ControlFutureTransactionEntity> getControlFutureTransactionBySendingSystemCode();
}

And the max date I get by a simple loop in the code, and I want to make the code faster by one query, to add the max date to the method in the repository. for some reason this option is hard to find in google.

Thanks a lot !

Answer 1

You have two options:

Option 1 (aggregation framework):

db.collection.aggregate([ {$match:{sendingSystemCode:999}} , {$group:{_id:"the_max_date" ,maxDate:{$max:"$createdDate"}}}        ])

Option 2 ( find/sort/limit):

db.collection.find({sendingSystemCode:999}).sort({createdDate:-1}).limit(1)