Node.js Sequelize js如何获得关联模型的平均值(聚合值)
我正在尝试使用sequelize获得模型“用户”的关联模型“评级”的平均评级Node.js Sequelize js如何获得关联模型的平均值(聚合值),node.js,orm,sequelize.js,associations,aggregate-functions,Node.js,Orm,Sequelize.js,Associations,Aggregate Functions,我正在尝试使用sequelize获得模型“用户”的关联模型“评级”的平均评级 sequelize.sync({logging: false}).then(()=>{ return Model.Rating.findAll({ attributes: [[Sequelize.fn('avg', Sequelize.col('stars')),'rating']] }) }).then(res => { res = res.map(r => r.get())
sequelize.sync({logging: false}).then(()=>{
return Model.Rating.findAll({
attributes: [[Sequelize.fn('avg', Sequelize.col('stars')),'rating']]
})
}).then(res => {
res = res.map(r => r.get())
console.log(res);
})
直接从“评级”模型尝试时,我得到了正确的响应:
然而,当试图通过“User”的关联来做同样的事情时,我得到的是单独的值,而不是平均值
sequelize.sync({logging: false}).then(()=>{
return Model.User.findOne({
where: {id: 7},
include : [{
model: Model.Rating, as: 'seller_rating',
attributes: [[Sequelize.fn('avg', Sequelize.col('stars')),'rating']]
}],
attributes: {
exclude: ['password']
},
group: ['seller_rating.id', 'user.id'],
})
}).then(res => {
res = res.get()
res.seller_rating = res.seller_rating.map(r => r.get())
console.log(res)
})
我不得不在组中添加“seller_rating.id”和“user.id”,否则sequelize会抛出错误
{
id: 7,
email: 'example@gmail.com',
createdAt: 2020-01-20T09:07:47.101Z,
updatedAt: 2020-01-21T08:58:52.036Z,
seller_rating: [
{ rating: '4.0000000000000000' },
{ rating: '3.0000000000000000' }
]
}
以下是用户和评级的模型
用户:
let User = sequelize.define('user', {
email: {type: Sequelize.STRING, unique: true, allowNull: false},
password : {type: Sequelize.STRING, },
})
let Rating = sequelize.define('rating', {
seller_id: {
type: Sequelize.INTEGER,
references: {model: User, key: 'id'},
unique: 'rateObject'
},
buyer_id: {
type: Sequelize.INTEGER,
references: {model: User, key: 'id'},
unique: 'rateObject'
},
stars: {
type: Sequelize.INTEGER,
validate: {
min: 1,
max: 5
},
allowNull: false
}
})
Rating.belongsTo(User,{ onDelete: 'cascade', foreignKey: 'seller_id'})
Rating.belongsTo(User,{ onDelete: 'cascade', foreignKey: 'buyer_id'})
User.hasMany(Rating, { foreignKey: 'seller_id', as: 'seller_rating'})
User.hasMany(Rating, { foreignKey: 'buyer_id', as: 'buyer_rating'})
评级:
let User = sequelize.define('user', {
email: {type: Sequelize.STRING, unique: true, allowNull: false},
password : {type: Sequelize.STRING, },
})
let Rating = sequelize.define('rating', {
seller_id: {
type: Sequelize.INTEGER,
references: {model: User, key: 'id'},
unique: 'rateObject'
},
buyer_id: {
type: Sequelize.INTEGER,
references: {model: User, key: 'id'},
unique: 'rateObject'
},
stars: {
type: Sequelize.INTEGER,
validate: {
min: 1,
max: 5
},
allowNull: false
}
})
Rating.belongsTo(User,{ onDelete: 'cascade', foreignKey: 'seller_id'})
Rating.belongsTo(User,{ onDelete: 'cascade', foreignKey: 'buyer_id'})
User.hasMany(Rating, { foreignKey: 'seller_id', as: 'seller_rating'})
User.hasMany(Rating, { foreignKey: 'buyer_id', as: 'buyer_rating'})
此解决方案适用于您:
Model.User.findOne({
where: { id: 7 },
attributes: [
[Sequelize.fn('AVG', Sequelize.col('seller_rating.stars')), 'avgRating'],
],
include: [
{
model: Model.Rating,
as: 'seller_rating',
attributes: [],
},
],
raw: true,
group: ['User.id'],
}).then((res) => console.log(res));