need help about database query builder

e.g

table: points

userId   |  totalPoints

1    |    1000
2    |    500
3    |    2000
....................
...........


so ,
i have a 20 to 30 sets of raw data[userId/totalPoints] that i want to update points table.

condition:
1.  if raw data [total points] is greater then original value that presents in database , then i need to update points table data with raw data .

2. if raw data [total points] is less then original value that presents in database , then i raw data (totalpoints) will be added with original value present in database.


so, how can i write database query for this problem??


Thanks for help.

Try soemthing like that:

Code:

UPDATE  points
SET     totalPoints = IF(totalPoints < 2000, 2000, totalPoints )

If you are:

• Using Active Record
  
• Updating a specific user and know their user_id
  

Then you could try something like this:

Code:

$newTotalPoints = 123456;

$qry = $this->db->select('totalPoints')->get_where('points',array('user_id'=>$user_id));

if( $qry->num_rows() ) {

   $currentTotalPoints = $qry->row_array()['totalPoints'];

   if( $newTotalPoints > $currentTotalPoints ) {

       $this->db->where('user_id',$user_id)->update('points',array('totalPoints'=>$newTotalPoints));

   } else if( $newTotalPoints < $currentTotalPoints ) {

       $this->db->where('user_id',$user_id)->update('points',array('totalPoints'=>$newTotalPoints+$currentTotalPoints));

   }

}