Codeigniter如何通过此查询排序

Question

这是我的查询，其中我仅显示9行，但按日期排序的人应该如何以及在何处添加我（在当前查询中按排序）

$q = $this->db->get('exchange_rate, country', 9,'exchange_rate.CountryId = country.CountryId');

Answer 1

try this format, just as an example

         $this->db->select('a.exchange_rate, b.country');
         $this->db->from('exchange_rate a');
         $this->db->join('country b','b.CountryId = a.CountryId');
         $this->db->order_by("yourOrderByColumn",'DESC');
         $this->db->limit(9);
         $query = $this->db->get();

Answer 2

http://ellislab.com/codeigniter/user-guide/database/active_record.html

you will get good idea about codeignitor databse conceepts

Answer 3

$this->db->from('exchange_rate');
$this->db->join('country', 'exchange_rate.CountryId = country.CountryId');
$this->db->limit(9);
$this->db->order_by("date", "asc");
$query = $this->db->get();

For more information go to codeigniter documentation

Answer 4

First, you're using the get() method terribly wrong. Where you got that syntax, I have no idea.

Since get() is a method that triggers the query, all parameter methods that add your query's details - like where() , order_by() , etc. - should come before it.

$this->db->order_by('column', 'ASC');
$this->db->get('table_name');

I'd also recommend using a JOIN instead of selecting two tables with a weird WHERE sequence.

$this->db->select('column, another_column, etc');
$this->db->from('table');
$this->db->join('another_table', 'another_table.column = table.column');
$this->db->order_by('sort', 'DESC');
$query = $this->db->get();