If you use supabase and running this command and it returns something like this 'The following models were commented out because we couldn't retrieve columns for them. Please check your privileges.' or something similar regarding privileges, the solution is to go to your SQL editor from supabase and put this command and execute it

GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO postgres;
GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public TO postgres;

I just fired up a new project to verify that this works:

npm init
npm install prisma --save-dev

Add .env file with database information, e.g.

DATABASE_URL="postgresql://postgres.xxxxyyyyzzzz:passpasspass@aws-0-us-west-1.pooler.supabase.com:5432/postgres?schema=public"

where postgres.xxxxyyyyzzzz is they user name, and passpasspass is the password

Then run

npx prisma init --datasource-provider postgresql

And finally:

npx prisma db pull

Which produces the prisma/schema.prisma file, first few lines:

/// This model contains row level security and requires additional setup for migrations. Visit https://pris.ly/d/row-level-security for more info.
model locations {
  location_name    String             @db.VarChar(255)
  street_address   String             @db.VarChar(255)
  city             String             @db.VarChar(100)
  state_province   String             @db.VarChar(100)
  postal_code      String             @db.VarChar(20)
  unit_number      String?            @db.VarChar(20)
  notes            String?
  id               String             @id @default(dbgenerated("gen_random_uuid()")) @db.Uuid
  service_requests service_requests[]
}

Edit: Then I added a new table Foo, and ran npx prisma db pull again, adds the table to the schema

/// This model or at least one of its fields has comments in the database, and requires an additional setup for migrations: Read more: https://pris.ly/d/database-comments
/// This model contains row level security and requires additional setup for migrations. Visit https://pris.ly/d/row-level-security for more info.
model foo {
  id         BigInt   @id @default(autoincrement())
  created_at DateTime @default(now()) @db.Timestamptz(6)
}