Database
[{"_id":ObjectId("61779e5c1e4ed11e96301ccd"),"title":"Clothing","metaTitle":"","slug":"hello","content":""},{"_id":ObjectId("61779e8d1e4ed11e96301ccf"),"parentId":ObjectId("61779e5c1e4ed11e96301ccd"),"title":"Shoe","metaTitle":"","slug":"","content":""},{"_id":ObjectId("6177c1cd6d3e170ae58c89c3"),"title":"Electric","metaTitle":"","slug":"","content":""}]
Query
db.collection.find({},{"parentId":{$cond:{if:"$parentId",then:"$parentId",else:""}},"title":1,"slug":1})