private function processJoinDefinition()
    {
        if (isset($this->definition['join']) && is_array($this->definition['join'])) {
            
            foreach ($this->definition['join'] as $join) {
                
                $array = new IsAssoc($join);
                
                if ($array->isAssoc()) {
                    $this->join[] = [
                        'table' => $join['table'],
                        'as' => $join['as'],
                        'by' => $join['by'],
                        'cond' => $join['condition']
                    ];
                } else {
                    $this->join[] = [
                        'table' => $join[0],
                        'as' => $join[1],
                        'by' => $join[2],
                        'cond' => $join[3]
                    ];
                }
            }
        }
    }