XPath Expression to Calculate total amount for order details

extkml · November 4th, 2009, 06:31 AM

I have a xml file like this

PHP Code:


			


<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<orders>

<order orderDate="1/1/2009" orderNo="1">

<customer id="nnghiem" name="nguyen nghiem"/>

<item id="item-1" price="25000" quantity="0"/>

<item id="item-2" price="22000" quantity="3"/>

</order>

<order orderDate="2/2/2009" orderNo="2">

<customer id="lp" name="lampard"/>

<item id="item-1" price="25000" quantity="2"/>

<item id="item-2" price="22000" quantity="8"/>

</order>

<order orderDate="3/3/2007" orderNo="3">

<customer id="nnghiem" name="nguyen nghiem"/>

<item id="item-1" price="25000" quantity="7"/>

<item id="item-2" price="22000" quantity="6"/>

</order>

</orders>

Now i want to calculate total amount for each order

this is my xsl file

PHP Code:


			
                    <xsl:for-each select="/orders/order">

                        <tr>

                            <td> <xsl:value-of select="@orderNo"></xsl:value-of> </td>

                            <td> <xsl:value-of select="@orderDate"></xsl:value-of> </td>

                            <td> <xsl:value-of select="customer/@name"></xsl:value-of> </td>

                    <td> <xsl:value-of select="sum(item/@quantity * item/@price)"></xsl:value-of></td>

                        </tr>                        

                    </xsl:for-each>

When i transform xml+xsl => html, an error occured at the line

PHP Code:


			
<xsl:value-of select="sum(item/@quantity * item/@price)"></xsl:value-of>

I can only guess that my xpath - expression is not correct, i also tried this:

PHP Code:


			
<xsl:value-of select="sum(item/@quantity * @price)"></xsl:value-of>

But i also got the same problem. How can i fix this?

I need some advices, i've just learnt XSL for 1 week.

Thanks for your attention

mhkay · November 4th, 2009, 06:47 AM

You could get a long way just by googling for "XSLT sum of price times quantity".

In XSLT 2.0 the solution is sum(item/(@price * @quantity))

In XSLT 1.0 it's much harder. The only clean solution is a recursive traversal of the items in which you pass the accumulated sum as a parameter and add in the value of @price * @quantity before making the recursive call to process the next item. You'll often find this in XSLT books as a textbook example of recursive template processing.

Of course, sum(item/@quantity * item/@price) doesn't work. You can't take a set of attribute nodes and multiply it by another set of attribute nodes.

extkml · November 26th, 2009, 11:34 AM

thanks for your advice, I got the solution