HELP: Data can't be updated to table

[gilabola]

This is what i want the process to be – once the user click the ‘addbtn’, the system will first check whether the product is already in the table ‘cart’ by comparing the PRO_ID. If the PRO_ID is not in the table, PRO_ID,PRO_NAME,PRO_PRICE,MEM_ID,CART_QUANTITY will be inserted to the table.

 

But if the PRO_ID  already exist in the table, it will only update the table by only adding 1 to the CART_QUANTITY

 

The problem now, the system still inserting the PRO_ID,PRO_NAME,PRO_PRICE,MEM_ID,CART_QUANTITY to the table even when the same PRO_ID and MEM_ID exist in the table.

 

I attached the jpeg example of the table.

 

Please guide me. Thank you

 

<?php
if (isset($_POST["addcart"]))
{
$result2 = mysql_query("select PRO_ID from cart where PRO_ID = $PRO_ID and MEM_ID = $memid");
if ($result2 == 0)
 {
$PRO_ID=$_POST["Product_ID"];
$PRO_NAME=$_POST["Product_Name"];
$PRO_PRICE=$_POST["Product_Price"];

mysql_query("insert into cart (PRO_ID,PRO_NAME,PRO_PRICE,MEM_ID,CART_QUANTITY) values ('$PRO_ID','$PRO_NAME',$PRO_PRICE,$memid,1)");
header ("Location:member_carts.php");

} 
else if (result2==$PRO_ID)
 {
	// update product quantity in cart table
	mysql_query("UPDATE cart 
	        SET CART_QUANTITY = CART_QUANTITY + 1
			WHERE MEM_ID = '$memid' AND PRO_ID = $PRO_ID");		

	header ("Location:member_carts.php");	
}	
}	
?>

 

[attachment deleted by admin]

[DaiLaughing]

You are using your product id variable before it contains anything.

[PFMaBiSmAd]

mysql_query() returns a result resource for a SELECT query that executes without any errors, not actual data. You must fetch data from a result resource or you can also use functions like mysql_num_rows() to find out how many rows are contained in a result set. These are the basics for using php/mysql that are covered in all the books, tutorials, and the php.net documentation for what you are attempting to do.