select
	"Parent"."id" as "Parent_id",
	"Parent__Parent_child"."id" as "Parent__Parent_child_id",
	"Parent__Parent_child"."parent_id" as "Parent__Parent_child_parent_id",
	"Parent__Parent_child"."sub_child_name" as "Parent__Parent_child_sub_child_name"
from
	"parent" "Parent"
left join "child" "Parent__Parent_child" on
	"Parent__Parent_child"."parent_id" = Parent.parentId
where
	("Parent"."id" = $1)

@Entity()
export class Parent {
  @PrimaryColumn()
  id: string;

  @OneToOne(() => Child, (item) => item.parent)
  child?: Child;
}

@Entity("child")
export class Child {
  @PrimaryGeneratedColumn("uuid")
  id?: string;

  @Column({ type: "varchar", name: "parent_id", nullable: false, unique: true })
  parentId: string;

  @Column({ type: "varchar", name: "sub_child_name", nullable: false })
  subChildName: string;

  @OneToOne(() => Parent, (item) => item.child, { onDelete: "CASCADE" })
  @JoinColumn({ name: "parent_id", referencedColumnName: "id" })
  parent?: Parent;

  @ManyToOne(() => SubChild, (item) => item.childs, { onDelete: "CASCADE" })
  @JoinColumn([
    { name: "parent_id", referencedColumnName: "parentId" },
    { name: "sub_child_name", referencedColumnName: "childName" },
  ])
  subChild?: SubChild;
}

@Entity("sub_child")
@Unique("UQ_ parent_childName", ["parentId", "childName"])
export class SubChild {
  @PrimaryGeneratedColumn("uuid")
  id?: string;

  @Column()
  parentId: string;

  @Column()
  childName: string;

  @ManyToOne(() => Parent)
  parent: Parent;

  @OneToMany(() => Child, (item) => item.subChild)
  childs?: Child[];
}

const parent = await this.parentRepo.find({
      where: {
        id: "AAA"
      },
      select: ["id"],
      relations: ["child"],
    });

public async up(queryRunner: QueryRunner): Promise<void> {
        await queryRunner.query(`CREATE TABLE "parent" ("id" character varying NOT NULL, CONSTRAINT "PK_bf93c41ee1ae1649869ebd05617" PRIMARY KEY ("id"))`);
        await queryRunner.query(`CREATE TABLE "sub_child" ("id" uuid NOT NULL DEFAULT uuid_generate_v4(), "parentId" character varying NOT NULL, "childName" character varying NOT NULL, CONSTRAINT "UQ_ parent_childName" UNIQUE ("parentId", "childName"), CONSTRAINT "PK_e4a8dfeabd861a2c907e0a89e8c" PRIMARY KEY ("id"))`);
        await queryRunner.query(`CREATE TABLE "child" ("id" uuid NOT NULL DEFAULT uuid_generate_v4(), "parent_id" character varying NOT NULL, "sub_child_name" character varying NOT NULL, CONSTRAINT "UQ_4157a24f3378c1e06ae3a942868" UNIQUE ("parent_id"), CONSTRAINT "REL_4157a24f3378c1e06ae3a94286" UNIQUE ("parent_id"), CONSTRAINT "PK_4609b9b323ca37c6bc435ec4b6b" PRIMARY KEY ("id"))`);
        await queryRunner.query(`ALTER TABLE "sub_child" ADD CONSTRAINT "FK_541d7c27a2543472b351cd56295" FOREIGN KEY ("parentId") REFERENCES "parent"("id") ON DELETE NO ACTION ON UPDATE NO ACTION`);
        await queryRunner.query(`ALTER TABLE "child" ADD CONSTRAINT "FK_4157a24f3378c1e06ae3a942868" FOREIGN KEY ("parent_id") REFERENCES "parent"("id") ON DELETE CASCADE ON UPDATE NO ACTION`);
        await queryRunner.query(`ALTER TABLE "child" ADD CONSTRAINT "FK_f1190fc68522883602bede4e872" FOREIGN KEY ("parent_id", "sub_child_name") REFERENCES "sub_child"("parentId","childName") ON DELETE CASCADE ON UPDATE NO ACTION`);
    }