Read out the value of the related discriminator map - symfony

Question

I have an Order entity, what has a property called $name. This property is an entity called Heading and has a one to one relation to the order table.
Also, this heading has a discrimiatormap, here are the annotation:
/**
* #ORM\Entity
* #ORM\Table(name="Heading")
* #ORM\InheritanceType("SINGLE_TABLE")
* #ORM\DiscriminatorMap({
* "simple"="SimpleName",
* "separated"="SeparatedName",
* "company"="CompanyName"
* })
*/
Foreign keys are set properly.
What I want to achieve, to get the name of the user.
I am trying to get a column, called fullName with the name of user.
This how I try:
$queryBuilder->leftJoin(
'e.name',
'h',
);
$queryBuilder->addSelect('
(
CASE
WHEN h INSTANCE OF '.SimpleName::class.' THEN h.name
WHEN h INSTANCE OF '.CompanyName::class.' THEN h.company
WHEN h INSTANCE OF '.SeparatedName::class." THEN CONCAT(h.first_name, ' ', h.last_name)
ELSE ''
END
)
AS fullName
");
It fails, it says, Utils\\Model\\Heading\\Heading has no field or association named name.
I've tried THEN h.SimpleName, but I also get no field for SimpleName.
If I just using a string there like ssss, ccccc, spspsps, then it's cool, I am getting the result, so the CASE WHEN ELSE is works.
How can I reference to those fields? What should I wrote after the THEN in the 3 cases?
CompanyName, SimpleName and SeparatedName are extends the Heading class.
Here is the CompanyName class for example:
/**
* #ORM\Entity
*/
class CompanyName extends Heading
{
/**
* #ORM\Column(type="string", nullable=true)
*/
private ?string $companyName = null;
public static function create(?string $companyName = null): self
{
$object = new self();
$object->companyName = $companyName;
return $object;
}
public function __toString(): string
{
return $this->companyName ?? '';
}
public function getType(): string
{
return 'company';
}
public function getCompanyName(): ?string
{
return $this->companyName;
}
public function setCompanyName(?string $companyName): self
{
$this->companyName = $companyName;
return $this;
}
}

Answer 1

Meanwhile I've changed the h to orderHeading, and here is the solution.
protected function createQueryBuilder(): QueryBuilder
{
$queryBuilder = parent::createQueryBuilder();
$queryBuilder->leftJoin(
'e.name',
'orderHeading'
);
$queryBuilder->leftJoin(SeparatedName::class, 'separatedName', Join::WITH, 'orderHeading.id = separatedName.id')
->leftJoin(SimpleName::class, 'simpleName', Join::WITH, 'orderHeading.id = simpleName.id')
->leftJoin(CompanyName::class, 'companyName', Join::WITH, 'orderHeading.id = companyName.id');
$queryBuilder->resetDQLPart('groupBy');
$queryBuilder->addGroupBy('e');
return $queryBuilder;
}
.....
protected function createCountQueryBuilder(): QueryBuilder
{
$queryBuilder = parent::createCountQueryBuilder();
$queryBuilder->leftJoin(
'e.name',
'orderHeading'
);
$queryBuilder->leftJoin(SeparatedName::class, 'separatedName', Join::WITH, 'orderHeading.id = separatedName.id')
->leftJoin(SimpleName::class, 'simpleName', Join::WITH, 'orderHeading.id = simpleName.id')
->leftJoin(CompanyName::class, 'companyName', Join::WITH, 'orderHeading.id = companyName.id');
return $queryBuilder;
}
and after that you can reference to these columns as
$propertyMap['fullName'] = new ColumnSqlDescriptor('
CASE
WHEN orderHeading INSTANCE OF '.SimpleName::class.' THEN simpleName.name
WHEN orderHeading INSTANCE OF '.CompanyName::class.' THEN companyName.companyName
WHEN orderHeading INSTANCE OF '.SeparatedName::class." THEN CONCAT(separatedName.firstName, ' ', separatedName.lastName)
ELSE 'NA'
END
");