Restriction in select command

Question

in a alv report i have used select statement on 2 columns say crtno , range to select entries from a table1 db.
and i want to select again crtno (with few same entries) from another table2 in db.
what i want is to EXCLUDE earlier selected entries in crt no.
how can i EXCLUDE earlier selected entries from my i_tab.??
my code:
SELECT ZPACKH~CRTNO
   ZPACKH~RANGE
  INTO CORRESPONDING FIELDS OF TABLE I_LABOR
   FROM ZPACKH INNER JOIN ZCOMBO_MAT
  ON ZPACKHRANGE = ZCOMBO_MATMATNR.
IF I_LABOR[] IS NOT INITIAL.
     LOOP AT I_LABOR.
                 I_LABOR-LABOR = 'CM'.
                MODIFY I_LABOR INDEX SY-TABIX.
                CLEAR I_LABOR.
        ENDLOOP.
ENDIF.
SELECT ZPACKI~CRTNO
    ZPACKI~MATNR
    INTO CORRESPONDING FIELDS OF TABLE I_LABOR
    FROM ZPACKI INNER JOIN MARA
    ON ZPACKIMATNR EQ MARAMATNR.
some entries for crtno is same in zpackh and zpacki....... thats what i want select statement to not select already present entries in i_tab.

Answer 1

Use the [STABLE|http://help.sap.com/abapdocu_70/en/ABAPSORT_ITAB.htm#&ABAP_ADDITION_1@1@] option in the [SORT|http://help.sap.com/abapdocu_70/en/ABAPSORT_ITAB.htm] statement, so [DELETE|http://help.sap.com/abapdocu_70/en/ABAPDELETE_ITAB_SHORTREF.htm] [ADJACENT DUPLICATES|http://help.sap.com/abapdocu_70/en/ABAPDELETE_DUPLICATES.htm] will keep first record.
So
- SELECT FROM best table INTO itab
- SELECT FROM worst table APPENDING itab
- SORT itab BY key STABLE
- DELETE ADJACENT DUPLICATES FROM itab COMPARING key
Regards,
Raymond