Pass a NULL value to numeric parameter via Yii in PostgreSQL - postgresql

Question

I have written a function in PostgreSQL with a single parameter of type NUMERIC. I am attempting to call that function from a webapp developed using the Yii framework via the SqlDataProvider component. However, each time the parameter value is left empty, I keep getting the following error:
Ivalid input syntax for type 'numeric'.
Whenever I try to execute the function directly via PhpPgAdmin, everything seems to work flawlessly.
Below is the code for the discussed PL/pgSQL function search(..):
search("itemcode" character varying DEFAULT NULL, "taxpercentage" numeric DEFAULT NULL)
LANGUAGE plpgsql
AS $$
BEGIN
SELECT * FROM item WHERE (itemcode IS NULL OR item.item_code LIKE itemcode||'%')
AND (taxpercentage IS NULL OR item.tax_percentage = taxpercentage);
END;
$$;
In the Yii model, I have also created a search function which in turn calls the database-level PL/pgSQL function:
public function search()
{
$count=Yii::app()->db->createCommand("SELECT COUNT(*) FROM search('$this->item_code','$this->tax_percentage')")->queryScalar();
$sql="SELECT * FROM search('$this->item_code','$this->tax_percentage')";
$dataProvider=new CSqlDataProvider($sql, array(
'totalItemCount'=>$count,
'pagination'=>array(
'pageSize'=>10,
),
));
return $dataProvider;
}
How can I pass a NULL value to parameter of type NUMERIC?
All help will be much appreciated. Thanks in advance.

Answer 1

I solved it by checking for empty in the search function and using parameterized query. So the modified function is
public function search()
{
if(empty($this->tax_percentage))
$this->tax_percentage=null;
$count=Yii::app()->db->createCommand("SELECT COUNT(*) FROM search(:item_code,:tax_percentage)")->queryScalar();
$sql="SELECT * FROM search('$this->item_code','$this->tax_percentage')";
$dataProvider=new CSqlDataProvider($sql, array(
'params' => array(':item_code' => $this->item_code,':tax_percentage' => $this->tax_percentage),
'totalItemCount'=>$count,
'pagination'=>array(
'pageSize'=>10,
),
));
return $dataProvider;
}