循环 at 和 sy-subrc 关系

Question

I have this problem during loop statement.

I have a loop:

loop at lt assigning <ls> where <condition> (im using loop instead of reaf table coz i need to use GE and LE logical statements)
     if sy-subrc = 0.
      result = <ls>-FIELD.
     else.
      result = ''.
     endif.
endloop.

So the problem is it skips the sy-subrc check. When loop executes and doesnt find a record (sy-subrc = 4) it doesnt assign '' into the result field and keepeing the initial statement instead.

Whats the problem?

Answer 1

The return code is set after the loop (same for select and other loop structures). So you need something like:

 loop at lt assigning <ls> where <condition>"(im using loop instead of reaf table coz i need to use GE and LE logical statements)
 endloop.
 if sy-subrc = 0.
  result = <ls>-FIELD.
 else.
  result = ''.
 endif.

In this case you should use a read -statement (you mention a problem with GE/LE - this may be worth another question).

Now you loop on all entries.

As an alternative you could stop after the first entry:

result = ''. "Initialize for not-found-entry.
loop at lt assigning <ls> where <condition>.
  result = <ls>-FIELD. "Take the found entry
  exit. "Stop after first entry
endloop.

Without the exit you would get the last entry. If the order is relevant, you may also add a relevant sort.