db={"advertisements":[{"_id":ObjectId("650c053c0d606e3db1e882e1"),"name":"mtesting","short_desc":"sfdhgsfghdf","description":"xcvsdfgsdfg","status":1,"createdAt":ISODate("2023-09-21T14:26:28.397+05:30"),"__v":0,"amount":NumberDecimal("100"),"categoryID":ObjectId("6500738369cb6aaf6b26eea8"),"createdBy":ObjectId("64fad2dab11e29c07682bb2e"),"slug":"testing","subCategoryId":ObjectId("6500738369cb6aaf6b26eeab")}],"categories":[{"_id":ObjectId("6500738369cb6aaf6b26eea8"),"categoryName":"Real Estate","categoryBgImage":"static/bgimage/dbrr3om91aw000000000","status":"Active","subCategory":[{"subCategoryName":"Apartments","status":"Active","_id":ObjectId("6500738369cb6aaf6b26eeaa"),"createdAt":ISODate("2023-09-12T19:49:47.365+05:30")},{"subCategoryName":"Townhouses","status":"Active","_id":ObjectId("6500738369cb6aaf6b26eeab"),"createdAt":ISODate("2023-09-12T19:49:47.365+05:30")}],"createdAt":ISODate("2023-09-12T19:49:47.366+05:30"),"__v":0}]}

db.advertisements.aggregate([{$match:{"slug":"testing"}},{$limit:1},{"$lookup":{"from":"categories","localField":"categoryID","foreignField":"_id","as":"categoriesData"}},{$unwind:{path:"$categoriesData",preserveNullAndEmptyArrays:true}},{$project:{_id:1,name:1,slug:1,amount:{$concat:[{$toString:"$amount"}]},createdAt:{$dateToString:{format:"%Y-%m-%d %H:%m",date:"$createdAt"}},status:1,short_desc:1,description:1,categoryName:"$categoriesData.categoryName",subCategoryName:{$getField:{input:{$first:{$filter:{input:"$categoriesData.subCategory",cond:{$eq:["$$this._id","$subCategoryId"]}}}},field:"subCategoryName"}}}}])