如何从codeigniter中的数据库同时从同一列获取最小值和最大值？

Question

I want to get the minimum and maximum values, at the same time, with one query in CodeIgniter.

Here is my code snippet:

$this->db->select_min('table.col1');
$this->db->select_max('table.col1');
$this->db->select('table.col2');
$this->db->from('atm_rates');
$this->db->order_by('table.col2');
$query = $this->db->get();
return $query->result_array();

Answer 1

You can try this select:

$this->db->select('MAX(col1), MIN(col1)'); $query = $this->db->get('table');

OR

$sql = "SELECT MAX(col1) AS max, MIN(col1) as min FROM table; $query = $this->db->query($sql)->get();

And then

return $query->result_array();