protected function getColumnCommentSqlDefinition(Column $column, $tableName)
    {
        // passing 'null' is to remove column comment
        $comment = (strcasecmp($column->getComment(), 'NULL') !== 0)
                 ? $this->getConnection()->quote($column->getComment())
                 : 'NULL';

        return sprintf(
            'COMMENT ON COLUMN %s.%s IS %s;',
            $this->quoteTableName($tableName),
            $this->quoteColumnName($column->getName()),
            $comment
        );
    }