code: public function dropColumn($table, $column)
      {
          $time = $this->beginCommand("drop column $column from table $table");
          $this->db->createCommand()->dropColumn($table, $column)->execute();
          $this->endCommand($time);
      }
docs: Builds and executes a SQL statement for dropping a DB column.
  @param string $table the table whose column is to be dropped. The name will be properly quoted by the method.
  @param string $column the name of the column to be dropped. The name will be properly quoted by the method.