Sequelize 限制包含关联

Question

我在使用 Sequelize 限制结果和包含关联模型时遇到问题。

以下生成正确的结果，以 10 为限并正确排序。

Visit.findAll({
  limit: 10,
  order: 'updatedAt DESC',
}).success(function(visits) {
  res.jsonp(visits);
}).failure(function(err) {
  res.jsonp(err);
})

SQL

SELECT * FROM `Visits` ORDER BY updatedAt DESC LIMIT 10;

但是，当我添加关联时，它突然限制了子查询，因此由于结果集有限，排序永远不会发生。

Visit.findAll({
  limit: 10,
  order: 'updatedAt DESC',
  include: [
    { model: Account, required: true }
  ]
}).success(function(visits) {
  res.jsonp(visits);
}).failure(function(err) {
  res.jsonp(err);
})

SQL

SELECT 
  `Visits`.* 
FROM 
  (SELECT 
    `Visits`.*, `Account`.`id` AS `Account.id`, `Account`.`email` AS `Account.email`, `Account`.`password` AS `Account.password`, `Account`.`role` AS `Account.role`, `Account`.`active` AS `Account.active`, `Account`.`createdAt` AS `Account.createdAt`, `Account`.`updatedAt` AS `Account.updatedAt`, `Account`.`practice_id` AS `Account.practice_id` 
  FROM 
    `Visits` INNER JOIN `Accounts` AS `Account` ON `Account`.`id` = `visits`.`account_id` LIMIT 10) AS `visits` 
ORDER BY updatedAt DESC;

我所期待的是对顶级查询的限制是这样的：

SELECT 
  ...
FROM 
  (SELECT ...) AS `Visits`
ORDER BY `Visits`.updatedAt DESC LIMIT 10
LIMIT 10;

Answer 1

您不应在订单中的单个字符串中同时使用键和方向。来自 docs:

'username DESC', // will return username DESC -- i.e. don't do it!

正确的解法是：

order: ['updatedAt', 'DESC']

完整的工作示例：

'use strict';

var Sequelize = require('sequelize');
var sequelize = new Sequelize(
    'test', // database
    'test', // username
    'test', // password
    {
        host: 'localhost',
        dialect: 'postgres'
    }
);

var Customer = sequelize.define('Customer', {
    firstName: {type: Sequelize.STRING},
    lastName: {type: Sequelize.STRING}
});

var Order = sequelize.define('Order', {
    amount: {type: Sequelize.FLOAT}
});

var firstCustomer;

Customer.hasMany(Order, {constraints: true});
Order.belongsTo(Customer, {constraints: true});

sequelize.sync({force: true})
    .then(function () {
        return Customer.create({firstName: 'Test', lastName: 'Testerson'});
    })
    .then(function (author1) {
        firstCustomer = author1;
        return Order.create({CustomerId: firstCustomer.id, amount: 10});
    })
    .then(function () {
        return Order.create({CustomerId: firstCustomer.id, amount: 20})
    })
    .then(function () {
        return Order.findAll({
            limit: 10,
            include: [Customer],
            order: [
                ['updatedAt', 'DESC']
            ]
        });
    })
    .then(function displayResults(results) {
        results.forEach(function (c) {
            console.dir(c.toJSON());
        });
    })
    .then(function () {
        process.exit(0);
    });

产生：

SELECT "Order"."id", "Order"."amount", "Order"."createdAt", "Order"."updatedAt", "Order"."CustomerId", "Customer"."id" AS "Customer.id", "Customer"."firstName" AS "Customer.firstName", "Customer"."lastName" AS "Customer.lastName", "Customer"."createdAt" AS "Customer.createdAt", "Customer"."updatedAt" AS "Customer.updatedAt" FROM "Orders" AS "Order" LEFT OUTER JOIN "Customers" AS "Customer" ON "Order"."CustomerId" = "Customer"."id" ORDER BY "Order"."updatedAt" DESC LIMIT 10;

Answer 2

订单字段键模型order: ['FieldOrder', 'DESC']

例如：

 db.ModelA.findAll({
    include: [{
        model: db.ModelB
    }],
    order: ['CreatedDateModelA', 'DESC']
})
.then(function(response){
}, function(err){
})

订单字段包含型号 order: [ModelInclude,'FieldOrder', 'DESC']

例如：

db.ModelA.findAll({
    include: [{
        model: db.ModelB
    }],
    order: [db.ModelB,'CreatedDateModelA', 'DESC']
})
.then(function(response){

}, function(err){

})

Sequelize 限制包含关联

Sequelize limit include association

javascript

mysql

sequelize.js