Doctrine 2 get the First and Last Entry of a Table with the QueryBuilder

Question

I got two tables with an ManyToOne Relationship (Many "Entity1" to One "Entity2").

Now I need to get the first and the last Entity from Entity1 which belongs to Entity2. The amounts of "Entity1" for a "Entity2" will be counted in the "entity1_in_entity2_id" Column.

Also there is a entity2_id Column in Entity1 to indentify Entity2.

I know I could achieve this with an nativeQuery with Subselects and I already did this, but now I want to do this with the QueryBuilder but I don't know how. I want to try MAX() and MIN() to get the last and first one.

The var $id is set by the function which calls the function this snippet is from.

I tried some coding by myself, this I what I got so far:

    $qb = $this->createQueryBuilder('e');
    $qb->select()
        ->where('e.entity2_id = ' . $id)
        ->orwhere($qb->expr()->orX(
                $qb->expr()->min('e.entity1_in_entity2_id'),
                $qb->expr()->max('e.entity1_in_entity2_id')
            ));

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

By now I get the following error

[Syntax Error] line 0, col 114: Error: Expected =, <, <=, <>, >, >=, !=, got 'OR'

And don't worry about the names, I must use dummy data sadly, would be easier to explain if use the real table names :D

Answer 1

Based on doctrine documentation: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/query-builder.html#the-expr-class

It should be something like:

   ->add('where', $qb->expr()->orX(
       $qb->expr()->eq('u.id', $qb->expr()->eq('e.entity1_in_entity2_id', $qb->expr()->min('e.entity1_in_entity2_id')),
       $qb->expr()->eq('u.id', $qb->expr()->eq('e.entity1_in_entity2_id', $qb->expr()->max('e.entity1_in_entity2_id'))
   ))

if you really want to use expr, you can also just use

->addSelect('MAX(e.entity1_in_entity2_id) as maxid,MIN(e.entity1_in_entity2_id) as minid')
->having('e.entity1_in_entity2_id IN(minid,maxid)
or
->having('e.entity1_in_entity2_id = minid OR e.entity1_in_entity2_id = maxid')