Crystal Reports report list

Message

   Dear Gurus,

I have data in table as follows:

Inv_No  ItemCode     Desc          Amount
1             11              7up            10
1             12              pepsi          25
1             13              mirinda       15
2             11              7up            12
2             13              mirinda       16

I need to get list report as per item code as follows:

Sales report
Invno     7up           pepsi         mirinda     .......
1            10              25              13
2            12              0                 16
continues.......

Is it possible?

I have done as follows:
In crystal report => made group (INVNO) and ITEMNO => 
add formula field with 

Sum (field,condfield, condition) but gives me error
like sum ({sales.amount},{sales.itemcode}, {sales.invno})
Error message : a group field is not allowed here {sales.invno}

Any help or idea would be appreciated.

Best regardsm

BT