slection field Fields validations

  LOOP AT s_bukrs.
    IF s_bukrs-low IS NOT INITIAL.
      SELECT COUNT(*) FROM t001 WHERE bukrs = s_bukrs-low.
      IF sy-subrc NE 0.
        MESSAGE e006(vb) WITH s_bukrs-low.

      ENDIF.
    ENDIF.
    IF s_bukrs-high IS NOT INITIAL.
      SELECT COUNT(*) FROM t001 WHERE bukrs = s_bukrs-high.
      IF sy-subrc NE 0.
        MESSAGE e006(vb) WITH s_bukrs-high.

      ENDIF.
    ENDIF.
  ENDLOOP.