https://forum.codeigniter.com/archive/index.php?thread-64966.html
```
$this->db->select('SQL_CALC_FOUND_ROWS *', false);
//避免重復查詢,如果限定字段卻查出所有,將此處'*'換成id之類的
//此處正常帶limit查詢語句
// 獲取總條數
$query = $this->db->query('SELECT FOUND_ROWS() AS `count`');
$totalRows = $query->row()->count;
```
