Mongodb在UPDATE操作中使用$pull的操作方法

{$pull: {<field1>: <value|condition>, <field2>: <value|condition>, ...}}

db.stores.insertMany([
    {
        _id:1, 
        fruits: ["apples", "pears", "oranges", "grapes", "bananas"],
        vegetables: ["carrots", "celery", "squash", "carrots"]
    },
    {
        _id:2, 
        fruits: ["plums", "kiwis", "oranges", "bananas", "apples"],
        vegetables: ["broccoli", "zucchini", "carrots", "onions"]
    }
    ])

db.stores.updateMany({},{$pull:{fruits:{$in: ["apples", "oranges"]}, vegetables: "carrots"}})

db.profile.insertOne({_id: 1, votes:[3,5,6,7,7,8]})

db.profile.updateOne({_id: 1}, {$pull: {votes: {$gte: 6}}})

try{
   db.profileBulkWrite.bulkWrite([
       {
           insertOne: {
               "document": {_id: 1, votes: [3,5,6,7,7,8]}
           }
       },
       {
           updateOne: {
               "filter": {_id: 1},
               "update": {$pull: {votes: {$gte: 6}}}
           }
       },
       {
           updateOne: {
               "filter": {_id: 1},
               "update": {$pull: {votes: {$lte: 3}}}
           }
       }
       ])
} catch (error){
    print(error)
}

db.profileBulkWrite.find()

db.survey.insertMany([
    {_id: 1, results: [{item: "A", score: 5}, {item: "B", score: 8}]},
    {_id: 2, results: [{item: "C", score: 8}, {item: "B", score: 4}]}
])

db.survey.updateMany({},{$pull: {results: {score: 8, item: "B"}}})

db.survey.insertMany([
    {_id: 1, results: [
        {item: "A", score: 5, answers:[{q:1, a:4}, {q:2, a:6}]}, 
        {item: "B", score: 8, answers:[{q:1, a:8}, {q:2, a:9}]}
    ]},
    {_id: 2, results: [
        {item: "C", score: 8, answers:[{q:1, a:8}, {q:2, a:7}]}, 
        {item: "B", score: 4, answers:[{q:1, a:0}, {q:2, a:8}]}
    ]}
])

db.survey.updateMany({},{ $pull: { "results": {
    answers: {
        $elemMatch: {
            q: 2,
            a: { $gte: 8 }
        }
    }
} } })