Spring Data – MongoDB – Aggregation how to project all fields of grouped reference document

I have 2 documents, Topic and comment. Each topic has many comments and the documents look like this: @Document public class Topic { @Id private String id; @Indexed(unique = true) @NotBlank private String title; } @Document public class Comment { @NotBlank private String text; @Indexed @NotBlank private String topic; // id of topic @CreatedDate @Indexed…

Need to join 3 collection for mongodb to find the aggregated data

My knowledge in mongodb is less. I have store list as store collection which has only store basic details Store collection: [ { “id”: “5dc25092d972e71c3b3e6e87”, “name”: “Chad store”, }, { “id”: “5dc2899bfd1ea02f0fceb9ab”, “name”: “Bad store”, } ] I have signal-records collection which has the multiple signals records for each store. signal records are like no.…