CI 下 mysql 查询语句的写法--心得

1.查询的条件按mysql的语法顺序编码，相同的操作放一起

2.要查询的字段写明白。尽量少用或不用*;

----------------------------------------------

参照mysql 语法

select field1,field2 from table where 1 group by field1 order by field2 asc limit 5;

CI写法（Active Record 模式）：

$this->db->select('field1,field2');
$this->db->join('table2', 'table2.id = tabl1.id','left');
$this->db->where(array());
$this->db->order_by('field2','asc');
$this->db->group_by('field1');
$this->db->limit(5);
$this->db->get('table');