Specific pricing based on quantity entered

[lee115034]

Perhaps I'm not looking in the right place, so any help would be appreciated. I have a cart that needs to calculate a specific price based on a quantity entered off of a sliding scale for a class. A quantity of 1 is charged $2000, the second person on the order gets in for $750 (so total of 2750), then 3rd or more get in for 500 each (so 4 would be 2000+750+500+500). Any easy way to set this?

Thanks in advance!

[Ray Borduin]

Yes, you can do this. How I would do it would depend on my application and how many items I sell and how much variation in this formula I would need to support. For the most flexability, you would create two additional columns in your cart named "SecondDiscount" and "MultipleDiscount".

Then you can go to the calculations tab and update the totalprice calculation from:

[Price] * [Quantity]

to:

([Price] * [Quantity]) - (([Quantity]>1)?(([Quantity]-1)*[SecondDiscount]):0) - (([Quantity>2])?(([Quantity]-2)*[MultipleDiscount]):0)

And then your values when you entered into the cart would be:

Price: 2000
SecondDiscount: 1250
MultipleDiscount: 250

[lee115034]

Ray -- thanks for the message, but I'm confused a bit :)

I can get the calculation working in PHP by doing this:

<?php
// set vars
$Quantity = $_POST['quantity']; // selected on previous page
$Price = $recordset['price'] // variable and set in DB, pulled in recordset
// calculate!
if ($Quantity == 1)
$Price = $Price;
elseif ($Quantity == 2)
$Price = $Price+750;
else //($Quantity >= 3)
$Price = $Price+750+(($Quantity-2)*500);
?>

so...

I think the cart calculation should be something like this:

(([Quantity]=1)?([Price]) OR
(([Quantity]=2)?([Price])+750 OR
(([Quantity]>2)?([Price]+750)*(([Quantity]-2)*500))

I'd prefer for this not to appear as a discount line then calculate -- that will confuse the heck out of folks. This is similar to buy one at regular price, get a second for $10 and as many others as you want (3rd or more) for $5 each (insert numbers as needed).

Thoughts? Thanks again.

[Ray Borduin]

That is exactly what my calculation does.

Say that you had a cart with the columns:
Quantity: 2
Price: 2000
SecondDiscount: 1250
MultipleDiscount: 250

and you use the formula I gave of:
([Price] * [Quantity]) - (([Quantity]>1)?(([Quantity]-1)*[SecondDiscount]):0) - (([Quantity>0])?(([Quantity]-2)*[MultipleDiscount]):0)

I'll replace the numbers:
(2000 * 2) - ((2>1)?((2-1)*1250):0) - ((2>2)?((2-2)*250):0)

Then I'll combine a few:

(4000) - ((2>1)?(1250):0) - ((2>2)?(0):0)

the syntax ((x)?y:z) will return y if x is true and z if it is false, so above, ((2>1)?(1250):0) will return 1250 because it is true that 2>1. Using that I can further simplify the result to:

4000-1250 or 2750

Which is the expected result given your parameters.

What I did is I combined tha three line OR statement that you gave:

(([Quantity]=1)?([Price]) OR
(([Quantity]=2)?([Price])+750 OR
(([Quantity]>2)?([Price]+750)*(([Quantity]-2)*500))

and I used algebra and php to combine it into a single calculation.

[lee115034]

OK. I see how you're getting there.

Shouldn't the second calculation be [Quantity>2] instead of [Quantity>0]? If you have only one participant, 1>0 and will trigger the third part. In your sample, 2 is greater than zero and succeeds in that 2-2 = 0 nullifying that part but only works of quantity = 2.

There is also an add-to-cart element that does not use this calculation. Is best practice to add the two columns and add a separate calculation just for this part? (the separate part is that participants can make a deposit of $500 per person to hold space -- the rest is payable later). I can show you the sample page.

Thanks for your help again.

[Ray Borduin]

If it doesn't use the calculation, just set both of the columns for SecondDiscount and MultipleDiscount to zero.

Yes, it should be a 2... looks like you must be following the logic now that you are correcting it ;)

[lee115034]

I haven't had algebra since the mid 1980s and my brain hurts. I'll follow up with the result. I think this may occur more than once.

[lee115034]

Ray --

It works! Thanks again! I need to work through all the events to make sure this is water tight. :)

[Ray Borduin]

you are missing a "(" after the ? in both... it should be:

([Price] * [Quantity]) - (([Quantity]>1)?(([Quantity]-1)*[SecondDiscount]):0) - (([Quantity]>2)?(([Quantity]-2)*[MultipleDiscount]):0)

[lee115034]

Ray --

Just a followup as promised. One thing I didn't account for is that the base price of the event changes for each course. So rather than a discount, it has to be a surcharge based off of the base price:

2000+750+500+500=3750;
4000+750+500+500=4750

The base price is found in a database column for each event (class/seminar).

From all of your help and leveraging your logic, this formula works even of the base price for the event changes:

([Price]) + (([Quantity]>1)?([Price]-([Price]-[SecondDiscount])):0) + (([Quantity]>2)?(([Quantity]-2)*([Price]-([Price]-[MultipleDiscount]))):0)

Thank you so much for your help -- have a great weekend!