Raw queries with count() selected return strange non integer values

Bug description

While trying to work around this bug https://github.com/prisma/prisma/issues/14539 I noticed strange behavior when selected count().

How to reproduce

The following query:

const tagsWithCount = await prisma.$queryRawUnsafe<any[]>(`
      SELECT 
        t.id,
        t.name,
        t.path,
        COUNT(s.id) as _count
      FROM tags t
      LEFT JOIN posts_tags st on t.id = st.tag_id 
      LEFT JOIN posts s ON st.post_id = s.id
      GROUP BY
        t.id, 
        t.name, 
        t.path
      ORDER BY
        _count DESC
`)

returns rows like this:

{ 
id: 1, 
name: 'tag1', 
path: 'tag1', 
_count: 319n 
}

You may see that the _count field is not really integer. It has a strange suffix - “n”.

Expected behavior

The _count field in the resulting data set should only contain integer values.

Prisma information

model Post {
  id                      Int           @id @default(autoincrement()) @db.UnsignedInt
 
  postTags          PostTag[]

  @@map("posts")
}
model Tag {
  id                      Int             @id @default(autoincrement()) @db.UnsignedInt
  
  postTags           PostTag[]

  @@map("tags")
}

model PostTag {
  postId                 Int             @map("post_id") @db.UnsignedInt
  tagId                   Int             @map("tag_id") @db.UnsignedInt

  post                   Post           @relation(fields: [postId], references: [id], onDelete: Cascade)
  tag                     Tag             @relation(fields: [tagId], references: [id], onDelete: Cascade)

  @@id([postId, tagId])

  @@map("posts_tags")
}

Environment & setup

• OS: Docker: node:16-alpine (Linux)
• Database: Docker: mariadb:10.7
• Node.js version: v16.14.2

Prisma Version

    "@prisma/client": "^4.1.1"
    "prisma": "^4.1.1"

[janpio]

I don’t think that your table column types are relevant here @kkomelin. You are asking your database to return the result of COUNT() and that is indeed bigint for MariaDB: https://mariadb.com/kb/en/count/ In Javascript bigints can not be represented with normal Numbers, hence the Bigint as well on that side. Everything else would lead to potentially invalid data - and that is the one thing that is unacceptable for a ORM.

Prisma can not do better than to highlight specific thigns in the docs that might be unexpected (although technically correct and logical) to our users. In my discussion with @SevInf I basically tried to figure out if that is the case and worth the effort here. I could imagine a sentence “Note that if you use an aggregate function like COUNT() in SQL on some providers you might get a bigint value which initially might be not intuitive, but matches what the database returns.” and then a link to maybe how to handle strange bigint numbers.

[dariusj18]

This is because Prisma now “correctly” creates counts as bigint’s (int64) which is what mariadb/mysql and postgres return them as by default. BigInt is not fully supported, ex. I you try and serialize it nodejs’s default JSON serializer will throw an error.

I just ran into this, my solution is to cast the count as a string.