How to select all tree nodes of model hierarchy? children is association of model itself.

@Table
export class Department extends ADEntity {
    @ForeignKey(() => Department)
    @Column({
        type: DataType.INTEGER,
        allowNull: true,
    })
    parentId: number;

    @BelongsTo(() => Department)
    parent: Department;

    @Column({
        type: DataType.STRING,
        allowNull: false,
    })
    ou: string;

    @HasMany(() => Department)
    children: Department[];
    
    public static associations: {
        parent: Association<Department, Department>;
        children: Association<Department, Department>;
    };
}