（Doctrine ORM）如何通过多对一关系订购SELECT

Question

I have a database with types and categories (among other, unrelated things). Types have a many-to-one relationship with categories . What I want is to select all type rows, ordered first by category name and then by type weight and lastly by type name (all ascending). The critical part is that I want all the types with the same category to be grouped together in the result. Being the SQL neophyte that I am, I thought a simple join statement followed by appropriate order by statements would be sufficient. I was wrong. The result I'm getting makes no sense to me.

Actual result (type name - category name):

1. Aircraft Landing Strut - Aircraft
2. Aicraft Rotor Blade - Aircraft
3. Aircraft Wing - Aircraft
4. Bicycle Frame - Riding Cycles
5. Boat Bow - Watercraft
6. Boat Cargo Deck - Watercraft
7. Boulder Bottom - Rocks
8. Boulder Top - Rocks
9. Bowed Element - Others
10. Brick 1x1 w/Juice Carton Print - Bricks Printed
11. Brick 1x1 w/Milk Carton Print - Bricks Printed
12. Car Wash Brush Holder - Others
13. [etc.]

Expected result (type name - category name):

1. Aircraft Landing Strut - Aircraft
2. Aicraft Rotor Blade - Aircraft
3. Aircraft Wing - Aircraft
4. Brick 1x1 w/Juice Carton Print - Bricks Printed
5. Brick 1x1 w/Milk Carton Print - Bricks Printed
6. Bowed Element - Others
7. Car Wash Brush Holder - Others
8. Bicycle Frame - Riding Cycles
9. Boulder Bottom - Rocks
10. Boulder Top - Rocks
11. Boat Bow - Watercraft
12. Boat Cargo Deck - Watercraft
13. [etc.]

There are over 2,000 type rows, so the above lists are obviously very truncated. There are no errors. It's probably also important that the results are paginated (which has been working perfectly).

I'm using Doctrine 2.5.x with my own content management system. In the repository for the type entity I'm using QueryBuilder to construct the query as follows (the max result is a global setting and the first result is calculated outside the repository based on the current page number):

$qb = $this->createQueryBuilder('t');

$qb->select('t, c'); // omitting this does not change the result
$qb->join('t.category', 'c');
$qb->addOrderBy('c.name', 'ASC'); // this does not work as expected
$qb->addOrderBy('t.weight', 'ASC');
$qb->addOrderBy('t.name', 'ASC');
$qb->setMaxResults(20);
$qb->setFirstResult(0);

return $qb->getQuery()->getResult();

The resultant SQL statement is as follows:

SELECT b0_.ID AS ID_0, b0_.weight AS weight_1, b0_.name AS name_2, b0_.number AS number_3, b0_.name_alt AS name_alt_4, b0_.note AS note_5, b1_.ID AS ID_12, b1_.slug AS slug_13, b1_.name AS name_14, b1_.`desc` AS desc_15, b0_.cat_id AS cat_id_16 FROM types b0_ INNER JOIN categories b1_ ON b0_.cat_id = b1_.ID ORDER BY b1_.name ASC, b0_.weight ASC, b0_.name ASC LIMIT 20 OFFSET 0

The type entity is set up like this (with irrelevant fields ommitted):

/**
 * @Entity(repositoryClass="Nevermind\Repository\TypeRepository")
 * @Table(name="types", options={"collate"="utf8mb4_unicode_ci", "charset"="utf8mb4"})
 */
class Type {

    /**
     * @Id
     * @Column(type="integer", name="ID")
     * @GeneratedValue
     */
    protected $id;

    /**
     * @ManyToOne(targetEntity="Category", inversedBy="types", fetch="EAGER")
     * @JoinColumn(name="cat_id", referencedColumnName="ID")
     */
    protected $category;

    /**
     * @Column(type="integer")
     */
    protected $weight = 0;

    /**
     * @Column(type="string", unique=true)
     */
    protected $name = '';

    /**
     * @Column(type="string", unique=true, length=12)
     */
    protected $number = '';

    /**
     * @Column(type="string", nullable=true)
     */
    protected $name_alt;

    /**
     * @Column(type="text", nullable=true)
     */
    protected $note;

}

And the category entity is set up like this:

/**
 * @Entity(repositoryClass="Nevermind\Repository\DefaultRepository")
 * @Table(name="categories", options={"collate"="utf8mb4_unicode_ci", "charset"="utf8mb4"})
 */
class Category {

    /**
     * @Id
     * @Column(type="integer", name="ID")
     * @GeneratedValue
     */
    protected $id;

    /**
     * @Column(type="string", unique=true)
     */
    protected $slug = '';

    /**
     * @Column(type="string", nullable=true)
     */
    protected $name;

    /**
     * @Column(type="text", name="`desc`", nullable=true)
     */
    protected $desc;

    /**
     * @OneToMany(targetEntity="Type", mappedBy="category", fetch="EXTRA_LAZY", cascade={"persist", "remove"})
     * @OrderBy({"weight"="ASC", "name"="ASC"})
     */
    protected $types;

}

TypeRepository extends DefaultRepository which extends Doctrine's EntityRepository .

Answer 1

The weird ordering of the result was caused by the fact that the category name column is sometimes null (when displayed the name falls back to the transformed contents of the slug column, a change I'd completely forgotten about). Therefore simply changing the first order-by statement to be c.slug instead solves the problem. D'oh!

So remember, ordering by columns which can be null will cause strange results!

Answer 2

Have you tried

$qb->select('t, c');
...
$qb->orderBy('c.name', 'ASC'); // orderBy not addOrderBy for the first clause
$qb->addOrderBy('t.weight', 'ASC');
$qb->addOrderBy('t.name', 'ASC');
...