code: public function offsetExists($indexOrColumn)
      {
  
          if (is_numeric($indexOrColumn)) {
              return isset($this->expressions[(int)$indexOrColumn]);
          }
  
          try {
              return is_int($this->indexOfColumn($indexOrColumn));
          } catch (OutOfBoundsException $e) {
              return false;
          }
      }
docs: Checks if an expression exists at position $indexOrColumn or if an
  expression was added vor column $indexOrColumn
  
  @param string|int $indexOrColumn
  @return bool