This is from the thread in the SQL Server PowerPivot for Excel forum.

# Problem Description

Here's the sample data:

 STATUS WEEK SALES CUSTOMER INVOICE W01 \$150.00 A RETURN W02 \$120.00 B INVOICE W02 \$120.00 B INVOICE W02 \$130.00 C INVOICE W02 \$150.00 D INVOICE W03 \$130.00 E INVOICE W03 \$120.00 F RETURN W01 \$150.00 A INVOICE W04 \$100.00 G INVOICE W05 \$150.00 H RETURN W03 \$130.00 E RETURN W02 \$120.00 B RETURN W06 \$100.00 I INVOICE W06 \$100.00 I RETURN W05 \$150.00 H

What the user wanted was an output like this:

Without PowerPivo this is how the user was doing it:
"Create one pivot table filtered by INVOICE (WEEK in Columns, CUSTOMER in Rows) and second table filtered by RETURN (WEEK in Columns, CUSTOMER in Rows). Then manually calculate INVOICED pivot - RETURN pivot."

# Solution

Let's see how DAX formula in PowerPivot can help the user so that it eliminates the "manual" calculation.

So here are the steps:

## Step 1

Create two calculated measures:

Invoiced:=CALCULATE(SUM([SALES]),TABLENAME[STATUS]="INVOICE")

Returned:=CALCULATE(sum(DATA[SALES]),TABLENAME[STATUS]="RETURN")

## Step 2

Create one more calculated measure:

Invoiced-Returned:=[Invoiced]-[Returned]

Now from the usability standpoint, Hide measures created in step 1

Here's the screenshot of the PowerPivot Model:

## Step 3

Let's view this using PivotTables:

# Conclusion

In this post, we saw how to create custom calculation to handle invoices and returns using PowerPivot DAX Formula's.