DATE_FORMAT在Codeigniter Active Record的条件下

I want the Codeigniter equivalent of the sql below:

select * from `table_name` where DATE_FORMAT('table_name', "%Y-%m") < "YYYY-MM"

I have tried it but get NULL as the answer.Here is how i did it

$this->db->select_sum('column_name')->from('table_name')->where("DATE_FORMAT('column_name','%Y-%m') <","YYYY-MM")->get();

Thnx for any help?

Use without quotes column_name like DATE_FORMAT(column_name,'%Y-%m')

$this->db->select_sum('column_name')
         ->from('table_name')
         ->where("DATE_FORMAT(column_name,'%Y-%m') <","YYYY-MM")
         ->get();

try this

 $this->db->select_sum('column_name')
          ->from('table_name')
          ->where("DATE_FORMAT('column_name','%Y-%m') < YYYY-MM")
          ->get();

You can write your own clauses manually in where... read the docs

try this

$this->db->select("DATE_FORMAT(your_date_field, 'Year: %Y Month: %m Day: %d') AS formated_date");
$query = $this->db->get('your_table'); 

you just go through this THREADS