javascript - 如何使用 Sequelize.js 获取 MAX(id) GROUP BY 其他字段？

Question

我有一个 MySQL 数据库，它存储用符号表示的某些产品的价格。我现在想获得每个符号的最新价格。在纯 MySQL 中，我可以运行以下命令:

SELECT *
FROM prices
WHERE id IN (SELECT MAX(id) FROM prices GROUP BY symbol);

我现在想使用 Sequelize.js 做同样的事情.所以我尝试了以下几种变体:

const Sequelize = require('sequelize');

const sequelize = new Sequelize('mmjs', 'root', 'xxx', {host: 'localhost', dialect: 'mysql', logging: false, pool: {max: 5, min: 1, idle: 20000, acquire: 30000, handleDisconnects: true}, operatorsAliases: false,});

const Price = sequelize.define('price', {
    createdAt: {type: Sequelize.DATE(6), allowNull: false},
    symbol: {type: Sequelize.STRING, allowNull: false},
    bid: {type: Sequelize.FLOAT},
    ask: {type: Sequelize.FLOAT},
});

Price.findAll({
    attributes: [Sequelize.fn('max', Sequelize.col('id'))],
    group: ["symbol"]
}).then((maxIds) => {
    console.log(maxIds);
    console.log(maxIds.length);  // logs the correct length of 82
    return Price.findAll({
        where: {
            id: {
                [Sequelize.Op.in]: maxIds
            }
        }
    });
}).then(maxPrices => {
    console.log(maxPrices);
});

如评论中所述，maxIds.length 记录了 82 的正确长度。但之后我收到一条错误消息，提示 Unhandled rejection Error: Invalid value price。此外，console.log(maxIds); 给了我一些对象，这些对象似乎没有我期望的最大 id 值。下面是一个这样的对象的例子。

我在这里做错了什么？为什么它不像查询 SELECT MAX(id) FROM prices GROUP BY symbol 那样给我最大 ID？

price {
    dataValues: {},
    _previousDataValues: {},
    _changed: {},
    _modelOptions:
     { timestamps: true,
       validate: {},
       freezeTableName: false,
       underscored: false,
       underscoredAll: false,
       paranoid: false,
       rejectOnEmpty: false,
       whereCollection: null,
       schema: null,
       schemaDelimiter: '',
       defaultScope: {},
       scopes: [],
       indexes: [],
       name: [Object],
       omitNull: false,
       sequelize: [Object],
       hooks: {},
       uniqueKeys: {} },
    _options:
     { isNewRecord: false,
       _schema: null,
       _schemaDelimiter: '',
       raw: true,
       attributes: [Array] },
    __eagerlyLoadedAssociations: [],
    isNewRecord: false },

Answer 1

Sequelize 正在尝试将结果映射到价格模型 - 使用 raw: true 来防止这种情况发生。

Price.findAll({
    attributes: [Sequelize.fn('max', Sequelize.col('id'))],
    group: ["symbol"],
    raw: true,
})