code: public function buildColumn($query, $column)
      {
          // TODO add support for indexBy
          /* @var $modelClass ActiveRecord */
          $modelClass = $query->modelClass;
          $key = $this->quoteValue($modelClass::keyPrefix() . ':a:');
  
          return $this->build($query, "n=n+1 pks[n]=redis.call('HGET',$key .. pk," . $this->quoteValue($column) . ")", 'pks');
      }
docs: Builds a Lua script for finding a column
  @param ActiveQuery $query the query used to build the script
  @param string $column name of the column
  @return string