对于symfony和条令，“eq”子查询有一个错误：
没关系，没有错误：

public function getForums()
{
    $qb = $this->createQueryBuilder('fc');

    return $qb
        ->innerJoin('fc.versions', 'fcv')
        ->innerJoin('fc.versions', 'fcvl', 'WITH', $qb->expr()->in(
            'fcvl.id',
            $this->_em->createQueryBuilder()
                ->select('MAX(v.id)')
                ->from(ForumCategoryVersion::class, 'v')
                ->where('v.forumCategory = fc')
                ->getDQL()
        ))
        ->select('fc, fcv')
        ->getQuery()
        ->getResult();
}

替换 in 由 eq :

public function getForums()
{
    $qb = $this->createQueryBuilder('fc');

    return $qb
        ->innerJoin('fc.versions', 'fcv')
        ->innerJoin('fc.versions', 'fcvl', 'WITH', $qb->expr()->eq(
            'fcvl.id',
            $this->_em->createQueryBuilder()
                ->select('MAX(v.id)')
                ->from(ForumCategoryVersion::class, 'v')
                ->where('v.forumCategory = fc')
                ->getDQL()
        ))
        ->select('fc, fcv')
        ->getQuery()
        ->getResult();
}

我有一个错误：
[语法错误]第0行，第208列：错误：应为literal，得到'select'