About Rank number issue

Dear all,

We will do a rank number display Keyfigure,the Data layout as follow:

compcode PLant material group sales amount

1000 1000 A01 10

1000 1000 A02 20

2000 1000 A01 30

2000 1000 A02 40

Now we add sales amount again as a new Key figure to the query,and set the Calculate single values as "Rank number",then the result as follow:

compcode PLant material group sales amount sales amount(Rank number)

1000 1000 A01 10 1

1000 1000 A02 20 2

2000 1000 A01 30 1

2000 1000 A02 40 2

But we want get the result as follow,

compcode PLant material group sales amount sales amount(Rank number)

1000 1000 A01 10 1

1000 1000 A02 20 2

2000 1000 A01 30 3

2000 1000 A02 40 4

Who can help we?