MongoDB获得了我在项目管道中修改的字段总和

Question

我想计算avgamount作为sum 3字段= [balancelodeded + peripatorTueAmount -Walletusage]。 但是，这些字段可以为零，也可以根据条件为零（balancelodade，OperatoDueAmount，Walletusage）。我想总结应用条件后计算的最终值。是的，我需要从其他字段减去钱包。有人可以指导我如何在不更改项目管道中的字段名称的情况下执行此操作吗？

const result = await Bus.aggregate(
    [
        {
            $match: { ...filter },
        },
        {
            $project: {
                _id: 1,
                Amount1: '$Amount1',
                Amount2: { $cond: [{ $in: ['example1', dueFieldsConfigs] }, '$Amount2', 0] },
                Amount3: { $cond: [{ $in: ['example2', dueFieldsConfigs] }, '$Amount3', 0] },
                Amount4: { $cond: [{ $in: ['example3', dueFieldsConfigs] }, '$Amount4', 0] },
                avgAmount: { $sum: ['$Amount1', '$Amount2', '$Amount3'] },
            },
        },
        { $sort: sort },
        { $skip: skip },
        { $limit: limit },
    ],
);

Answer 1

您只是无法引用与创建它们相同的字段名称，最简单的方法就是在初始$ project阶段之后添加另一个阶段：

const result = await BusDayWise.aggregate(
    [
        {
            $match: {...filter}
        },
        {
            $project: {
                _id: 1,
                fromDate: "$fromDate",
                busNumber: "$busNumber",
                cardDueAmount: "$cardDueAmount",
                walletUsage: { $cond: [ {$in: ["digital", dueFieldsConfigs] }, "$walletUsage", 0 ]},
                balanceLoaded: { $cond: [ { $in: ["moneyLoaded", dueFieldsConfigs] }, "$balanceLoaded", 0] },
                operatorDueAmount: { $cond: [ { $in: ["contractual", dueFieldsConfigs] }, "$operatorPayout", 0] },
            }
        },
        {
            $addFields: {
                netDueAmount: { $sum: ["$balanceLoaded", "$operatorDueAmount", "$walletUsage"] },
            }
        },
        { $sort: sort },
        { $skip: skip },
        { $limit: limit },
    ]
)

如果您出于任何原因要放置它在同一阶段，您必须使用相同的条件来“计算”它们：

const result = await BusDayWise.aggregate(
    [
        {
            $match: { ...filter },
        },
        {
            $project: {
                _id: 1,
                fromDate: '$fromDate',
                busNumber: '$busNumber',
                cardDueAmount: '$cardDueAmount',
                walletUsage: { $cond: [{ $in: ['digital', dueFieldsConfigs] }, '$walletUsage', 0] },
                balanceLoaded: { $cond: [{ $in: ['moneyLoaded', dueFieldsConfigs] }, '$balanceLoaded', 0] },
                operatorDueAmount: { $cond: [{ $in: ['contractual', dueFieldsConfigs] }, '$operatorPayout', 0] },
                netDueAmount: {
                    $sum: [
                        { $cond: [{ $in: ['digital', dueFieldsConfigs] }, '$walletUsage', 0] },
                        { $cond: [{ $in: ['moneyLoaded', dueFieldsConfigs] }, '$balanceLoaded', 0] },
                        { $cond: [{ $in: ['contractual', dueFieldsConfigs] }, '$operatorPayout', 0] },
                    ],
                },
            },
        },
        { $sort: sort },
        { $skip: skip },
        { $limit: limit },
    ],
);