add or subtract value to a database field

[hema malini]

what is the equivalent of 

$qty = 3;

UPDATE products SET `available` = available - $qty WHERE (id = '3') AND (bagid = '3')   

?

[hema malini]

In notorm,

 $avail_data = array(

               'available' => "available - $quantity",

       );

 $availqty_update = $this->orm->products(array('id' => $id, 'bagid' => $bagid))->update($avail_data);

this makes the available field value 0.

[Allysson David]

If we take into consideration that you probably don't want to do a select before the update...

Then use a NotORM_Literal:

$avail_data = array(
    'available' => new NotORM_Literal('available - ?', $quantity),
);

[hema malini]

Thank you.

    Is it a select before the update is important? 

[Allysson David]

No. I only said that because if you already had the value from a
previous select you could calculate the subtraction on the php and
update it directly. Yours was a valid question.

2015-08-25 2:35 GMT-03:00, hema malini <svasa...@gmail.com>:
>
>>
>> Thank you.
>>
> Is it a select before the update is important?
>

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