$gte 和 $lte 在 Mongoose/MongoDB 中没有按预期工作

Question

我正在按价格范围过滤产品列表。有些价格范围很好，有些则不行。 当我单击（单选框）前端的价格范围时，它会通过价目表在后端进行处理。 看起来 $gte 和 $lte 没有按预期工作。我错过了什么吗？

反应前端 ---- 价目表：

export const prices = [
    {
        _id:0,
        name: 'Any',
        array: []
    },
    {
        _id:1,
        name: '$50 to $99',
        array: [50, 99]
    },
    {
        _id:2,
        name: '$100 to $199',
        array: [100, 199]
    },
    {
        _id:3,
        name: '$200 to $299',
        array: [200, 299]
    },
    {
        _id:4,
        name: '$300 to $399',
        array: [300, 399]
    },
    {
        _id:5,
        name: '$400 to $599',
        array: [400, 599]
    },
    {
        _id:6,
        name: '$600 to $799',
        array: [600, 799]
    },
]

NodeJS 后端 -------- 产品搜索列表：

exports.listBySearch = (req, res) => {
    let order = req.body.order ? req.body.order : "desc";
    let sortBy = req.body.sortBy ? req.body.sortBy : "_id";
    let limit = req.body.limit ? parseInt(req.body.limit) : 100;
    let skip = parseInt(req.body.skip);
    let findArgs = {};

    // console.log(order, sortBy, limit, skip, req.body.filters);
    // console.log("findArgs", findArgs);

    for (let key in req.body.filters) {
        if (req.body.filters[key].length > 0) {
            if (key === "price") {
                // gte -  greater than price [0-10]
                // lte - less than
                findArgs[key] = {
                    $gte: req.body.filters[key][0],
                    $lt: req.body.filters[key][1]
                };
                console.log(findArgs)
               // console.log -- { price: { '$gte': 50, '$lt': 99.99 } }
            } else {
                findArgs[key] = req.body.filters[key];
            }
        }
    }

    Product.find(findArgs)
        .select("-images")
        .populate("category")
        .sort([[sortBy, order]])
        .skip(skip)
        .limit(limit)
        .exec((err, data) => {
            if (err) {
                return res.status(400).json({
                    error: "Products not found"
                });
            }
            res.json({
                size: data.length,
                data
            });
        });
};

猫鼬 --------- 数据库：

{
    "_id" : ObjectId("6079a8d675db7021c00aa973"),
    "sold" : 5,
    "name" : "Java Book for Everyone",
    "description" : "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.",
    "price" : "75",
    "category" : ObjectId("605c9c94dcf90b34e8ec33e0"),
    "shipping" : false,
    "quantity" : 7,
    "createdAt" : ISODate("2021-04-16T15:10:14.626Z"),
    "updatedAt" : ISODate("2021-04-16T15:10:14.626Z"),
    "__v" : 0
}

Answer 1

mongoDB 文档中的价格是string 类型。 这就是为什么查询不起作用。 您想将 mongo 中的 price 值转换为 number 以进行比较。 修改查询以发送如下内容：

{
  $expr: {
    $and: [
      $gte: [{
        $toDouble: "$price"
      }, req.body.filters[key][0]],
      $lt: [{
        $toDouble: "$price"
      }, req.body.filters[key][1]]
    ]
  }
}