I am having a Mysql table item_details as below and want to get the delta diff for same item from next row sale_count.
item_id,sale_count
10001,32
10001,43
10001,50
10005,34
10005,48
10007,82
10007,82
Need result as below
item_id,diff
10001,11
10001,7
10005,14
10007,0
Please help here