CFML IF ELSE Problems

I am a novice at CFML and I need some help.

I am modifying a shopping cart programming that was built in CFML. I need to be able to adjust the price of an item depending on the quantity purchased. For example, the more a person buuys, the less expensive the per item cost becomes. Basically, each item will have up to 5 different prices depending on the amount purchased.

Anyway, I am trying to write an IF ELSE statement that looks at the quantity being purchased and then determines which price to charge the person. The information is taken from my MySQL database and includes the UNITPRICE of the item and then the 5 alternate prices and 5 quantity ranges. So basically, once a quantity is entered by the purchaser, the IF ELSE statement checks it against the upper limits of each quantity range, selects the correct price and then sets the original UNITPRICE of the item to be equal to the new "discounted" price (e.g., price1 is set if person purchases 1-100 of the same item; price2 is set if person purchases 101-200, and so on.)


The new price is then used in the calculation of the total, etc.

Here's part of the code:

<!--- // === [ Set default quantity number If no number is passed ONE SKU will be added ] === // --->
<cfparam name="Attributes.Quantity" default="1">
<!--- //Pull Product Data From Database // --->
<cfquery name="GetProduct" datasource="database" username="username" password="password">
SELECT SKU, ItemID, UnitPrice, ID, Name, Stock, Size, Weight, price1, price2, price3, price4, price5, range1, range2, range3, range4, range5 FROM ProductSKUs,
Products WHERE SKU = '#Attributes.SKU#' AND ItemID = ID
</cfquery>
<!---// We should have one Database match // --->
<cfif GetProduct.RecordCount EQ 1>
<!--- //Determine Array index (New Item vs. just an update) // --->
<!--- //If SKU exists, Update Quantity // --->
<cfif ListFind(ArrayToList(Session.Cart.SKU),GetProduct.SKU) NEQ 0>
<cfset ThisItem=ListFind(ArrayToList(Session.Cart.SKU),GetProduct.SKU)>
<!--- //Set Quantity // --->
<cflock timeout="2" throwontimeout="No" type="EXCLUSIVE" scope="SESSION">
<cfset Session.Cart.Quantity[ThisItem]=Session.Cart.Quantity[ThisItem] + Attributes.Quantity>
</cflock>



<!--THE IF ELSE -->

<cfif Session.Cart.Quantity[ThisItem] GTE GetProduct.range5>
<cfset GetProduct.UnitPrice=GetProduct.price5>
<cfelseif Session.Cart.Quantity[ThisItem] GTE GetProduct.range4>
<cfset GetProduct.UnitPrice=GetProduct.price4>
<cfelseif Session.Cart.Quantity[ThisItem] GTE GetProduct.range3>
<cfset GetProduct.UnitPrice=GetProduct.price3>
<cfelseif Session.Cart.Quantity[ThisItem] GTE GetProduct.range2>
<cfset GetProduct.UnitPrice=GetProduct.price2>
<cfelse>
<cfset GetProduct.UnitPrice=GetProduct.price1>
</cfif>

<!--END OF DISCOUNTPRICE STATEMENT





<!--- // === [ If SKU doesn't exist, add it to the end of the array ] === // --->
<cfelse>
<cfset ThisItem=ArrayLen(Session.Cart.SKU) +1 >

<!--- === [ Add to cart ] === // --->
<cflock timeout="5" throwontimeout="No" type="EXCLUSIVE" scope="SESSION">
<cfset Session.Cart.SKU[ThisItem]=GetProduct.SKU>
<cfset Session.Cart.ItemID[ThisItem]=GetProduct.ItemID>
<cfset Session.Cart.Name[ThisItem]=GetProduct.Name>
<cfset Session.Cart.Descrip[ThisItem]=GetProduct.Size>
<cfset Session.Cart.UnitPrice[ThisItem]=GetProduct.UnitPrice>
<cfset Session.Cart.UnitWeight[ThisItem]=GetProduct.Weight>
</cflock>

<cflock timeout="5" throwontimeout="No" type="EXCLUSIVE" scope="SESSION">
<cfset Session.Cart.Quantity[ThisItem]=Attributes.Quantity>
</cflock>

</cfif>


I'm getting the following error with this code:

An error occurred while evaluating the expression:


GetProduct.UnitPrice=GetProduct.price5



Error near line 219, column 9.
--------------------------------------------------------------------------------

Cannot add value to query


The operation you have requested is invalid. Only query columns can be added to query objects. It is likely that you have omitted the indexing brackets of a query column you are trying to set.

For example, can produce this error message. The correct syntax is



The error occurred while processing an element with a general identifier of (CFSET), occupying document position (219:3) to (219:48).

***********
Any help is appreciated. I can provide more code if necessary.

Thanks in advance.

I think the issue is that you are trying to change an element inside a query result set, which is more like an array than a "normal" variable". Try setting the unit price to a separate variable like "thisUnitPrice" and see if that works.

Yes, you may declare a local variable and change your price. If you want to change a query set value then you have to use QuerySetCell() function to do that. but in you code the value can be changed using another local variable.




<!--THE IF ELSE -->
<cfif Session.Cart.Quantity[ThisItem] GTE GetProduct.range5>
<cfset ThisUnitPrice=GetProduct.price5>
<cfelseif Session.Cart.Quantity[ThisItem] GTE GetProduct.range4>
<cfset ThisUnitPrice=GetProduct.price4>
<cfelseif Session.Cart.Quantity[ThisItem] GTE GetProduct.range3>
<cfset ThisUnitPrice=GetProduct.price3>
<cfelseif Session.Cart.Quantity[ThisItem] GTE GetProduct.range2>
<cfset ThisUnitPrice=GetProduct.price2>
<cfelse>
<cfset ThisUnitPrice=GetProduct.price1>
</cfif>

<!--- now you can add the changed prince to the cart --->
<cfset Session.Cart.UnitPrice[ThisItem]=ThisUnitPrice>