regarding of suming up the quantity fld

hii frnds

in my inernal table i am having data like

45000150 0010 5

45000023 0010 5

45000023 0020 5

45000023 0020 6

45000023 0020 10

45000023 0030 5

now my requiremnt is that i will have to get records in my table as

45000150 0010 5

45000023 0010 5

45000023 0020 21

45000023 0030 5

can anybody give me an idea how to do it .

regards

rohit