Question in ABAP syntax, read & insert data from internal table, while loop

Question

Hi, SDN Fellow.
I am from Java background and learnt ABAP, I don't usually write much ABAP code.
I am trying to implement the following logic in a RFC now.
I have one z-custom database table, the structure as the following:
It has two columns, with these sample data.
Says datable table is ZEMPMGRTAB.
EmployeeID,ManagerID
user10,user1
user9,user1
user8,user1
user7,user2
user6,user2
user5,user2
user4,user2
user2,user1
The logic is this:
I have a input parameter, userid. I am using this parameter to have a select statement to query the record into export table,EXPTAB 'LIKE' table ZEMPMGRTAB.
SELECT * FROM  ZEMPMGRTAB
  into table EXPTAB
   WHERE  EMPLOYEEID  = USERID.
Say, my parameter value, USERID ='USER4'.
Referring to the sample data above, I can get the record of this in my EXPTAB,
EmployeeID,ManagerID
user4,user2
Now, I want to iterately use the EXPTABLE-ManagerID
as the USERID input in SELECT statement, until it has no return result. Then, insert the new records in
EXPTAB.
In above new loop case, we will get this table content in EXPTAB,
EmployeeID,ManagerID
user4,user2
user2,user1
I kind of think of the pseudocode logic as below:
(These may not be a valid ABAP code, so I need help to convert/correct them)
DATA:
IWA TYEP ZZEMPMGRTAB,
ITAB
HASHED TABLE OF ZZEMPMGRTAB
WITH UNIQUE KEY EMPLOYEEID.
SELECT * FROM  ZEMPMGRTAB
  into table ITAB
   WHERE  EMPLOYEEID  = USERID.
*Question 1: I cannot insert a internal table to export table, it is *incompatible type, what is the alternative way fo this?
*Question 2: How can I access thedata of the internal table like this,ITAB-MANAGERID? As if I can, I would do this:
* IWA-EMPLOYEEE = ITAB-EMPLOYEEID. IWA-MANAGERID = IWA-MANAGERID. INSERT IWA INTO TABLE EXPTAB.
* Question 3: Is the 'NE NULL' - 'not equal to NULL' is right syntax?
IF ITAB NE NULL.
INSERT ITAB INTO EXPTAB.
ENDIF
* Question 4: Is my WHILE loop setup right here? And are the syntax right?
WHILE ITAB NE NULL.
SELECT * FROM  ZEMPMGRTAB
  into table ITAB
   WHERE  EMPLOYEEID  = ITAB-MANAGERID.
IF ITAB NE NULL.
INSERT ITAB INTO EXPTAB.
ENDIF
REFRESH ITAB.
ENDWHILE.
Assume all the syntax and logic are right, I should get this result:
EmployeeID,ManagerID
user4,user2
user2,user1
If I have a new entry in datable table,ZEMPMGRTAB like this:
user1,user0
My pseudocode logic will get this result:
EmployeeID,ManagerID
user4,user2
user2,user1
user1,user0
I truly appreciate if you can help me to validate the above syntax and pseudocode logic.
Thanks in advance.
KC

Answer 1

Hi,
FUNCTION ZGETSOMEINFO3.
*"*"Local Interface:
*"  IMPORTING
*"     VALUE(USERID) TYPE  AWTXT
*"     VALUE(FMTYPEID) TYPE  AWTXT
*"  EXPORTING
*"     VALUE(RETURN) TYPE  BAPIRETURN
*"  TABLES
*"      APPROVERT STRUCTURE  ZTAB_FMAPPROVER
*"      ACTOWNERT STRUCTURE  ZTAB_FMACTOWNER
DATA: T_RESULT TYPE STANDARD TABLE OF ZTAB_FMAPPROVER.
**Question 1: For this line, I got an error says "Program ''USERID" *not found. Is the syntax right, as the USERID is a parameter for the function.
perform add_line(USERID).
  ENDFUNCTION.
form add_line using i_user type ZTAB_FMAPPROVER.EMPLOYEEID
                    changing T_RESULT TYPE ZTAB_FMAPPROVER.
data: ls_row type ZTAB_FMAPPROVER.
* Get record for i_user
select single * into ls_row from ZTAB_FMAPPROVER
where EmployeeID = i_user.
if sy-subrc NE 0.
* Do nothing, there is not manager for this employee
else.
* Store result
QUESTION 2: I am still got stuck on this line of code. It still *says that "T_RESULT" is not an internal table "OCCURS n" *specification is missing. I thought the line: "T_RESULT TYPE *ZTAB_FMAPPROVER" means declare internal table, T_RESULT as type of ZTAB_FMAPPROVER". Am I understand it wrongly?
append ls_row to t_result.
* Call recursion
perform add_line using ls_row-ManagerID
                          changing t_result.
endif.
endform.
Thanks,
KC