我在尝试获取相关数据的总和时遇到了一些问题。
这是我的模式:
model Vote {
userId Int
user User @relation(fields: [userId], references: [id])
itemId Int
item Item @relation(fields: [itemId], references: [id])
value Int
@@id([userId, itemId])
}
model Item {
id Int @id @default(autoincrement())
userId Int
user User @relation(fields: [userId], references: [id])
listId Int
list List @relation(fields: [listId], references: [id])
votes Vote[]
body String @db.VarChar(255)
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
model List {
id Int @id @default(autoincrement())
userId Int
user User @relation(name: "Ownership", fields: [userId], references: [id])
items Item[]
sharedWith User[] @relation(name: "Shared")
title String @db.VarChar(255)
description String?
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
model User {
id Int @id @default(autoincrement())
email String @unique
password String
name String?
lists List[] @relation(name: "Ownership")
items Item[]
votes Vote[]
sharedWith List[] @relation(name: "Shared")
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
}
我想得到的是:
- 1 按 ID 列出
- 包含的列表项
- 以及每个项目的值总和(来自 Vote 表)。
这是我想出的:
prisma.list.findUnique({
where: { id },
include: {
items: {
include: {
votes: {
include: {
_sum: {
select: {
value: true,
},
},
},
},
},
},
},
})
我根据在网上找到的多个不同查询构建了查询(其中大部分在 Prisam Docs 中)。
我还注意到 Prisma Docs 缺少很多东西,比如(添加/删除相关数据 - 多对多关系)。是否有更好的文档或包含此类内容的示例项目?
谢谢!
最佳答案
目前无法将其作为单个查询。您可以做的是在取回这些值后对其求和。
我基于 StackOverflow 创建了一个类似的示例。给定以下 Prisma Schema:
// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema
datasource db {
provider = "postgresql"
url = env("DATABASE_URL")
}
generator client {
provider = "prisma-client-js"
}
model User {
id Int @id @default(autoincrement())
name String
votes Vote[]
questions Question[]
}
model Question {
id Int @id @default(autoincrement())
question String
votes Vote[]
user User @relation(fields: [userId], references: [id])
userId Int
}
model Vote {
id Int @id @default(autoincrement())
value Int @default(1)
questionId Int
question Question @relation(fields: [questionId], references: [id])
user User @relation(fields: [userId], references: [id])
userId Int
}
可以编写如下脚本:
import { PrismaClient } from "@prisma/client"
const prisma = new PrismaClient()
async function main() {
const users = await prisma.user.findMany({
include: {
questions: {
include: {
votes: {
select: {
value: true,
},
},
},
},
},
})
for (let user of users) {
for (let question of user.questions) {
let vote_sum = 0
for (let vote of question.votes) {
vote_sum += vote.value
}
;(question as any).vote_sum = vote_sum
}
}
console.dir(users, { depth: Infinity })
}
main().catch((err) => console.error(err))
然后在取回数据后对值求和。
如果这不适合您,我鼓励您写一个 feature request对于 Prisma 团队。
关于javascript - Prisma 3 关系聚合(求和),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/69788104/