db={movie:[{_id:"61d65a3431a314f4fc7e9170",image:"https://static.onecms.io/wp-content/uploads/sites/20/2021/08/25/spence...",title:"Spencer",rating:"R",length:"1 hr 57 min"}],wishlist:[{_id:"61ea4e67984f981ee529c008",user:"shangchi@gmail.com",movie:"61d65a3431a314f4fc7e9170"},{_id:"61ecf6f6c7b93b96890c9ebb",user:"shangchi@gmail.com",movie:"61e3a7bed4f5306388103156"},{_id:"61ecf73c9f651a07079c9641",user:"hello@gmail.com",movie:"61e3acc21d84993477d89a22"},{_id:"61ecf73e9f651a07079c9644",user:"hello@gmail.com",movie:"61d65a3431a314f4fc7e9170"}]}

db.movie.aggregate([{$lookup:{from:"wishlist",let:{movieId:"$_id"},pipeline:[{$match:{$expr:{$and:[{$eq:["$movie","$$movieId"]},{$eq:["$user","shangchi@gmail.com"]}]}}}],as:"wishlist"}}])