fix(core): allow joining a formula property

Closes #4759

packages/knex/src/query/QueryBuilderHelper.ts

@@ -226,8 +226,15 @@ export class QueryBuilderHelper {
       const params: Knex.Value[] = [];
 
       join.primaryKeys!.forEach((primaryKey, idx) => {
-        const left = `${join.ownerAlias}.${primaryKey}`;
         const right = `${join.alias}.${join.joinColumns![idx]}`;
+
+        if (join.prop.formula) {
+          const left = join.prop.formula(join.ownerAlias);
+          conditions.push(`${left} = ${this.knex.ref(right)}`);
+          return;
+        }
+
+        const left = join.prop.persist === false ? primaryKey : `${join.ownerAlias}.${primaryKey}`;
         conditions.push(`${this.knex.ref(left)} = ${this.knex.ref(right)}`);
       });
 

tests/issues/GH4759.test.ts

@@ -0,0 +1,101 @@
+import {
+  Collection,
+  DateType,
+  Entity,
+  ManyToOne,
+  OneToMany,
+  OneToOne,
+  PrimaryKey,
+  Property,
+  Ref,
+  ref,
+} from '@mikro-orm/core';
+import { MikroORM } from '@mikro-orm/postgresql';
+import { v4 } from 'uuid';
+
+@Entity()
+class Author {
+
+  @PrimaryKey()
+  id = v4();
+
+  @Property()
+  name!: string;
+
+  @OneToMany({
+    entity: () => Book,
+    mappedBy: 'author',
+  })
+  books = new Collection<Book>(this);
+
+  @OneToOne({
+    entity: () => Book,
+    ref: true,
+    formula: alias =>
+      `(select "b"."id"
+      from (
+        select "b"."author_id", min("b"."release_date") "release_date"
+        from "book" "b"
+        where "b"."author_id" = ${alias}."id"
+        group by "b"."author_id"
+      ) "s1"
+      join "book" "b"
+      on "b"."author_id" = "s1"."author_id"
+      and "b"."release_date" = "s1"."release_date")`,
+  })
+  firstBook?: Ref<Book>;
+
+  constructor(name: string) {
+    this.name = name;
+  }
+
+}
+
+@Entity()
+class Book {
+
+  @PrimaryKey()
+  id = v4();
+
+  @Property({ type: DateType })
+  releaseDate!: Date;
+
+  @Property()
+  name!: string;
+
+  @ManyToOne({
+    entity: () => Author,
+    ref: true,
+    inversedBy: 'books',
+  })
+  author!: Ref<Author>;
+
+  constructor(releaseDate: Date = new Date(), name: string, author: Author) {
+    this.releaseDate = releaseDate;
+    this.name = name;
+    this.author = ref((author));
+  }
+
+}
+
+let orm: MikroORM;
+
+beforeAll(async () => {
+  orm = await MikroORM.init({
+    entities: [Book, Author],
+    dbName: '4759',
+  });
+  await orm.schema.refreshDatabase();
+});
+
+afterAll(() => orm.close(true));
+
+test(`GH issue 4759`, async () => {
+  const author = new Author('John');
+  const book1 = new Book(new Date('2023-09-01'), 'My second book', author);
+  const book2 = new Book(new Date('2023-01-01'), 'My first book', author);
+  await orm.em.fork().persistAndFlush([author, book1, book2]);
+
+  const authorFound = await orm.em.find(Author, { firstBook: { name: 'My first book' } }, { populate: ['books', 'firstBook'] });
+  expect(authorFound[0].firstBook?.$.name).toBe('My first book');
+});