Problem with update data (reduce value)

Problem with update data (reduce value) - Printable Version

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Problem with update data (reduce value) - El Forum - 04-07-2012

[eluser]Carmichael[/eluser]

Code:
function reduce_credits($id, $credits)

   {

        $this->db->where('user_id', $id);

        $this->db->update($this->user_table, 'user_credits = user_credits - '.$credits.'');

   }

When I run that function it updates the user_credits column to 0 insted of reduce the current value. Why?

Problem with update data (reduce value) - El Forum - 04-07-2012

[eluser]Carmichael[/eluser]
I solved it

Code:
$this->db->where('user_id',$id);

        $this->db->set('user_credits','user_credits - ' . $credits, FALSE);

        $result = $this->db->update($this->user_table);

Problem with update data (reduce value) - El Forum - 04-07-2012

[eluser]Samus[/eluser]
Because the 2nd parameter is expected to be an array.

But explain what you're trying to do abit.

I'm a little confused here:

Code:
user_credits = user_credits - '.$credits.''

Something tells me you're trying to subtract the value of column 'user_credits' by $credits?