HI Spandana,
I know your problem have been solved. But for your information i will share one thing with you. The Value of sy-tabix always change when the some internal table operation are performed.
So for that
data lv_idx type sy-tabix.
loop at it_itab.
lv_idx = sy-tabix. " In the first line take the tabix value of the table.
read table it_itab2 . " after that statement TABIX value will be change. But if we can carry the tabix value in one variable at the starting of the loop then we don't need to worry about the value of system variable Tabix.
Modify it_itab index lv_idx. " LV_IDX contain the loop index.
endloop.
Regards.
Nishant Bansal