Sy-tabix in relation to LOOP AT and READ TABLE

Question

Hi All,
As per SAP documentation,
1) While looping through an internal table (LOOP AT), sy-tabix contains the index number of current row(for standard and sorted tables)
2)When successfully reading from an internal table(READ TABLE), sy-tabix is set to the index of the result row.
But what happens when READ TABLE is used while looping through another internal table?
i.e. Loop at TAB1...
write sy-tabix.
READ TABLE TAB2...
write sy-tabix.
endloop.
If we are looping through 1st row of TAB1 and the result of read statement is found in 3rd row of TAB2, I expected that sy-tabix before READ would be 1 and after the READ be 3.
But, I found that sy-tabix remains unchanged at 1. Can someone expalin why?
Thanks,
Jagan

Answer 1

Hi
If after reading the table TAB2 the system variable SY-TABIX has still the previous value, that menas the READ TABLE fails or it was read the first record of TAB2.
After READ TABLE TAB2 try to check the SY-SUBRC:
LOOP AT TAB1.
   WRITE: / 'TAB1 index:', SY-TABIX.
   READ TABLE TAB2 .........
   IF SY-SUBRC = 0.
     WRITE: 'TAB2 index:', SY-TABIX.
Try this:
DATA: BEGIN OF ITAB OCCURS 0,
        FIELD1,
      END   OF ITAB.
DATA: BEGIN OF ITAB2 OCCURS 0,
        FIELD1,
      END   OF ITAB2.
DATA: INDEX TYPE I.
DO 10 TIMES.
  APPEND ITAB.
ENDDO.
DO 10 TIMES.
  APPEND ITAB2.
ENDDO.
LOOP AT ITAB.
  WRITE: / 'ITAB:', SY-TABIX.
  INDEX = SY-TABIX + 2.
  READ TABLE ITAB2 INDEX INDEX.
  IF SY-SUBRC = 0.
    WRITE:  'ITAB2:', SY-TABIX.
  ENDIF.
ENDLOOP.
Max