Doctrine\DBAL\Query\QueryBuilder::verifyAllAliasesAreKnown PHP Method

    private function verifyAllAliasesAreKnown(array $knownAliases)
    {
        foreach ($this->sqlParts['join'] as $fromAlias => $joins) {
            if (!isset($knownAliases[$fromAlias])) {
                throw QueryException::unknownAlias($fromAlias, array_keys($knownAliases));
            }
        }
    }