Use Mysql to calculate a percentage of a total

Question

I'd like to charge £6.75 or 3% of a Net Order total - whichever is the greater.

£225 is the switching point to 3%.

How does this look:

if ($subtotal < 225) return 6.75; //where 6.75 is min charge
if ($subtotal > 225) {
$shipping = ($subtotal /100) * 3; //get 3%
$shipping = ROUND($shipping, 2); //round the figure
return $shipping;
}

Thanks

Answer 1

You can try like this

select IF(subtotal < 225 , 6.75, subtotal*.03) from table

Tested like this:

select IF(100 < 225 , 6.75, (100*.03)); // will return 6.75
select IF(300 < 225 , 6.75, (300*.03)); // will return 9

Answer 2

I would simply do:

$shipping = greatest(0.03*subtotal, 6.75)

I wouldn't build the constant 225 into the logic. If something changes, no one will know whether or not the constant should also be changed.