Why Collection showing only first field value

Question

I am just new to Magento and trying to get collection from sales/order_item model i don't know whether i am asking it right way or not but i am having following problem in getting values from db in magento 1.9.0.1

My db table looks like this

--------------------------------------------------------------------------
item_id    order_id    customid   ...... remaining column .....
   1           1           1
   2           2           1
   3           2           2
   4           2           1
   5           3           1
--------------------------------------------------------------------------

what i am trying to do is to get customid from order_id value which i have.

but it's showing only first value of customid which is 1 if order_id is 2

i am using below code

public function getCustomValue()
    {
        $id = $this->getRequest()->getParam('order_id');
        $collections = Mage::getModel('sales/order_item')->getCollection()
                    ->addFieldToFilter('order_id', $id);
        foreach ($collections as $c) {
            $customid = $c->getCustomid();
        }
        return $customid;
    }

So if i use

echo $this->getCustomValue();

it shows 1 only.

but as in my table order_id got 3 entry with 1,2,1 customid

Answer 1

There are logic issue in your code,you need to return array.Please $customid as Array type variable.

public function getCustomValue()
    {
        $id = $this->getRequest()->getParam('order_id');
        $collections = Mage::getModel('sales/order_item')->getCollection()
                    ->addFieldToFilter('order_id', $id);
    // define as array varible
    $customid=array();

        foreach ($collections as $c) {
        // assign the value at array
            $customid[] = $c->getCustomid();
        }
        return $customid;
    }