mongo 统计字段的长度并汇总

mongo.js

db.getCollection("mastersportal_counrse").aggregate([
    
    {
        "$project": {
            "overview": {
                "$strLenCP": "$overview"
            },
            "about": {
                "$strLenCP": "$about"
            }
        }
    },
    {
        
        $group: {
            _id: null,
            totalAmount: {
                $sum: {
                    $add: ["$overview", "$about"]
                }
            }
        }
    }
])