sql - Sequelize - 在不同条件下对相同关联进行两次计数

Question

我正在尝试根据不同的参数获取关联表中的两条记录:

// Models
var Customer = sequelize.define('Customer', {
    name: DataTypes.STRING,
});
var Invoice = sequelize.define('Invoice', {
    invoiceRef: DataTypes.STRING,
    status: {
        type: DataTypes.ENUM,
        values: ['UNPAID', 'PAID'],
        defaultValue: 'UNPAID'
    },
    isArchived: {
        type: DataTypes.BOOLEAN,
        defaultValue: false
    },
});
Invoice.associate = function(models) {
    Invoice.belongsTo(models.Customer);
}
Customer.associate = function (models) {
    Customer.hasMany(models.Invoice);
}


// Query
Customer.findAll({
    attributes: {
        include: [
            [models.Sequelize.fn("COUNT", models.Sequelize.fn("DISTINCT", models.Sequelize.col("Invoices.id"))), "totalInvoices"],
            [models.Sequelize.fn("COUNT", models.Sequelize.fn("DISTINCT", models.Sequelize.col("UnpaidInvoices.id"))), "unpaidInvoices"]
        ]
    },
    include: [
        {
            model: models.Invoice,
            where: { isArchived: false },
            attributes: [],
            required: false
        },
        {
            model: models.Invoice,
            where: { isArchived: false, status: 'UNPAID' },
            attributes: [],
            required: false
        },
    ],
    group: ['Customer.id']
})

问题是，当多次包含相同的关联表时，Sequelize 会为 SQL 查询中表的两个实例分配相同的名称:

LEFT OUTER JOIN Invoices AS Invoices ON Customer.id = Invoices.CustomerId AND Invoices.isArchived = 0
LEFT OUTER JOIN Invoices AS Invoices ON Customer.id = Invoices.CustomerId AND Invoices.isArchived = 0 AND Invoices.status = 'UNPAID'

有什么方法可以为查询中的连接表指定不同的名称吗？例如:

LEFT OUTER JOIN Invoices AS Invoices ON Customer.id = Invoices.CustomerId AND Invoices.isArchived = 0
LEFT OUTER JOIN Invoices AS UnpaidInvoices ON Customer.id = Invoices.CustomerId AND Invoices.isArchived = 0 AND Invoices.status = 'UNPAID'

Answer 1

我通常只加入一次，然后使用带有 SUM 的 CASE 语句，而不是使用 COUNT - 所有行都加入，这就是为什么你两者得到相同的结果。

attributes: {
  include: [
    // count paid using case/sum via `status` != 'UNPAID'
    [ sequelize.fn('sum', sequelize.literal("CASE WHEN (`Invoices`.`status` != 'UNPAID' THEN 1 ELSE 0 END")), 'paid_count' ],
    // count unpaid using case/sum via `status` = 'UNPAID'
    [ sequelize.fn('sum', sequelize.literal("CASE WHEN (`Invoices`.`status` = 'UNPAID' THEN 1 ELSE 0 END")), 'unpaid_count' ],
  ],
  // ...
},