Database
[{"_id":ObjectId("5f99cede36fd08653a3d4e92"),"accessions":{"sample_accessions":{"5f99ce9636fd08653a3d4e86":{"biosampleAccession":"SAMEA7494329","sraAccession":"ERS5250977","submissionAccession":"ERA3032827","status":"accepted"},"5f99ce9636fd08653a3d4e87":{"biosampleAccession":"SAMEA7494330","sraAccession":"ERS5250978","submissionAccession":"ERA3032827","status":"accepted"}}}}]
Query
db.collection.find({"accessions.sample_accessions.5f99ce9636fd08653a3d4e86":{$exists:true}},{"sample_doc":"$accessions.sample_accessions.5f99ce9636fd08653a3d4e86"})