yii\db\mysql\QueryBuilder::buildLimit PHP Method

    public function buildLimit($limit, $offset)
    {
        $sql = '';
        if ($this->hasLimit($limit)) {
            $sql = 'LIMIT ' . $limit;
            if ($this->hasOffset($offset)) {
                $sql .= ' OFFSET ' . $offset;
            }
        } elseif ($this->hasOffset($offset)) {
            // limit is not optional in MySQL
            // http://stackoverflow.com/a/271650/1106908
            // http://dev.mysql.com/doc/refman/5.0/en/select.html#idm47619502796240
            $sql = "LIMIT {$offset}, 18446744073709551615";
            // 2^64-1
        }
        return $sql;
    }