SFDC: Add a Rollup Summary Field
In my last post SFDC: Add a formula field , we see how to add a formula field and get
the total of each line item field
Another thing that's missing from the Invoice is a field
that aggregates all of the line items into one big invoice total. This is easy
to do if the objects are in a master-detail
relationship, because you can use a roll-up
Calculate a Total With a Roll-Up Summary Field
Now that you have the total for each line item, it makes
sense to add them all to get the invoice
total. Because the line items have a master-detail
relationship with the invoice, you can use a roll-up summary field to
calculate this value. Roll-up summary is
a special type of field that lets you aggregate information about related
detail (child) objects. In this case, you want to sum the value of each
Navigate back to the Invoice custom object page from Setup by clicking Create
> Objects and then clicking
In the Custom
Fields & Relationships related list click New.
Summary as the data type, and
For the Field
Label field, enter Invoice Total,
and click Next.
In the Summarized
Object list choose Line Items.
Up Type, select Sum.
In the Field
to Aggregate list choose Line Item
Verify that your screen looks like this. Then
click Next, Next and Save.
Try out the App:
To see the new Invoice Total formula field in action, you
only need to examine an invoice.
Click the Invoices
tab and then click an existing invoice.
Notice the new Invoice Total field that “rolls up” all the values from the detail
object’s Line Item Totals.
To get the Line Item Total field to appear on
the detail page, you’ll have to edit the page layout. (If you haven’t done that
yet, see SFDC: Modify a Page Layout). When you do, it should look like the
**This document is referred from salesforce help tutorials