Select query 'for all entries'

Question

Hello Friends,
       SELECT emp_id emp_name
       INTO corresponding fields of table itab_emp
       FROM employee
       for all entries in itab_dept
       WHERE emp_id = itab_dept_emp_id.
In the above select query we are using 'for all entries' for the internal table itab_dept.What will happen if the join fails?Will we get any data in the output table?
What is the prerequisites for using 'for all entries'.
Please advice me on this.
Regards
Ashish.

Answer 1

Hi
In this case all the records available in employee table are extracted into internal table itab_emp.
It is safe to check whether itab_dept is initial or not.
If it is initial then stop the select query.
Check the following program u will get an idea.
Also try this program by removing comment to 'REFRESH IT_LFA1'.
REPORT  ZBM_PG                                  .
TABLES: LFA1, EKKO.
DATA:
     IT_LFA1 TYPE TABLE OF LFA1 WITH NON-UNIQUE DEFAULT KEY INITIAL SIZE 10,
      IT_LFA1 TYPE TABLE OF LFA1 WITH HEADER LINE,
      IT_EKKO TYPE TABLE OF EKKO WITH HEADER LINE.
SELECT * FROM LFA1 INTO TABLE IT_LFA1 WHERE LIFNR EQ '0000001000' OR LIFNR EQ '0000001500'.
SELECT * FROM LFA1 INTO TABLE IT_LFA1 UP TO 1 ROWS.
refresh it_lfa1.
SELECT * FROM EKKO INTO TABLE IT_EKKO FOR ALL ENTRIES IN IT_LFA1 WHERE LIFNR = IT_LFA1-LIFNR.
LOOP AT IT_EKKO.
  WRITE: / IT_EKKO-LIFNR, IT_EKKO-EBELN.
ENDLOOP.
Reward me if it is useful