回送：MongoDB-将数组元素的字段更新为在UPDATE查询中不起作用的其他字段的总和

Question

存在带有变体作为数组的产品模型。我想将其priceInternational字段更新为（priceIndia * conversionRate + priceIndia * marginFactor）的总和。

以下是查询-

Product.update({ 
                and : [{ 
                    variants : { neq : [] }
                    },{ 
                        'variants.$[].priceInternational' : { neq : undefined }
                    }
                ]
            }, { 
                $set : {
                    'variants.$[].priceInternational' : { 
                        $sum : [{ 
                            $mul : { 'variants.$[].priceIndia' : conversionRate } 
                        }, { 
                            $mul : { 'variants.$[].priceIndia' : marginFactor } 
                        }] 
                    }
                } 
            }, {multi : true}, function(error, response){
                console.log(error, JSON.stringify(response))
            })

这给出了错误-

{ MongoError: The dollar ($) prefixed field '$sum' in 'variants.0.priceInternational.$sum' is not valid for storage.
at Function.MongoError.create (/Users/ankit/Projects/jaypore-ecommerce/jaypore-server/node_modules/mongodb-core/lib/error.js:45:10)
at toError (/Users/ankit/Projects/jaypore-ecommerce/jaypore-server/node_modules/mongodb/lib/utils.js:149:22)
at /Users/ankit/Projects/jaypore-ecommerce/jaypore-server/node_modules/mongodb/lib/collection.js:1029:39
at /Users/ankit/Projects/jaypore-ecommerce/jaypore-server/node_modules/mongodb-core/lib/connection/pool.js:544:18
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickDomainCallback (internal/process/next_tick.js:218:9)

请帮忙或提出其他可行的查询方法。