Question

I have a table with a column named balance.

if(mysqli_num_rows($get_bank_check_res) > 0){
    $display_block = "<p>your autho code is:</p>";
    $account_check = mysql_fetch_array($get_bank_check_res);
    $balance= $account_check > $grand_total_safe ? (balance - $grand_total_safe) : 0;
    $display_block .= "<p>your balance is: '".$balance."' </p>";

I received the warning : Undefined variable balance. Trying mysql_fetch_assoc() didn’t work either.

Answer 1

You get a row back with mysql_fetch_array, it doesn’t automagically create new variables for you. Ie your column is located here. Also, since you are using the MySQLi extension instead of mysql, it look like this:

$row = $get_bank_check_res->fetch_assoc();
$balance = $row["balance"];

then you can do you whatever math your doing using the values found inside your $row array.