How to Grouping in Report Designer?

In Sales Invoice user update same stock code few times   

When preview report, user wants to display the total QTY for same item

Solution : 

Step 1 : In Report Designer à Right Click Detail 1 à Group Footer 

Step 2: GroupFooter1 is created  

Step 3 : Move all items in Detail1 to groupFooter 1 

Step 4 : Delete the QTY field and drag again 

Ste p 5 : In QTY à Summary à Select Group

Step 6: when preview you will get result as below

Note : If you get result as below, please follow step number 4

Please refer attachment