http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb3990358411d1829f0000e829fbfe/content.htm

Specifying Columns Dynamically

DATA: ITAB TYPE STANDARD TABLE OF SPFLI,
      WA LIKE LINE OF ITAB.

DATA: LINE(72) TYPE C,
      LIST LIKE TABLE OF LINE(72).

LINE = ' CITYFROM CITYTO '.
APPEND LINE TO LIST.

SELECT DISTINCT (LIST)
       INTO CORRESPONDING FIELDS OF TABLE ITAB
       FROM SPFLI.

IF SY-SUBRC EQ 0.
  LOOP AT ITAB INTO WA.
    WRITE: / WA-CITYFROM, WA-CITYTO.
  ENDLOOP.
ENDIF.

The output is:

The internal table ITAB contains the columns of the database table SPFLI to be read. The DISTINCT addition in the SELECT clause means that the statement only reads those lines that have different contents in both of these columns. The result is a list of possible routes.

동적으로 변수값을 쿼리에 줄수 있다는걸 보여줄려고 하는것 같은데요

APPEND gs_line TO gt_list.

gs_line 값  CARRID CONNID는 SFLIGHT테이블의 필드값을 넘준것이고요

SELECT DISTINCT (gt_list) INTO TABLE gt_itab FROM sflight.

DISTINCT (gt_list) 는 DISTINCT CARRID CONNID 와 같은의미로 SFLIGHT테이블의 항공사ID(CARRID)와 운항연결ID(CONNID) 중복값을 제거해서 인터넬테이블에 담는 쿼리입니다.

그런데 위 쿼리는 이렇게 바꿔줘야 제대로 값이 나오네요.

SELECT DISTINCT (gt_list)
     INTO CORRESPONDING FIELDS OF TABLE gt_itab
   FROM sflight.

아하~!!! 그런 말이군요~^^  쉽게 이해가 되네요 ㅋㅋ 감사합니다.