the value you want to check for in the playerID column
conditionalTotal takes 3 arguments:
The column to total
The Conditional Column
The Value to check for
Say you had a color column and you wanted to now if any items where purchased with a color of red:
if($cartObName->ConditionalTotal("Quantity", "color", "red") > 0)) {
echo("there's a red item in the cart");
}