framework/db/mysql/QueryBuilder.php
public function addCommentOnColumn($table, $column, $comment)
    {
        // Strip existing comment which may include escaped quotes
        $definition = trim(preg_replace("/COMMENT '(?:''|[^'])*'/i", '',
            $this->getColumnDefinition($table, $column)));

        return 'ALTER TABLE ' . $this->db->quoteTableName($table)
            . ' CHANGE ' . $this->db->quoteColumnName($column)
            . ' ' . $this->db->quoteColumnName($column)
            . (empty($definition) ? '' : ' ' . $definition)
            . ' COMMENT ' . $this->db->quoteValue($comment);
    }
public function addCommentOnColumn($table, $column, $comment)
    {
        // Strip existing comment which may include escaped quotes
        $definition = trim(preg_replace("/COMMENT '(?:''|[^'])*'/i", '',
            $this->getColumnDefinition($table, $column)));

        return 'ALTER TABLE ' . $this->db->quoteTableName($table)
            . ' CHANGE ' . $this->db->quoteColumnName($column)
            . ' ' . $this->db->quoteColumnName($column)
            . (empty($definition) ? '' : ' ' . $definition)
            . ' COMMENT ' . $this->db->quoteValue($comment);
    }
{@inheritdoc}
@since 2.0.8