SELECT  DATE(N_DAY)             DT
       ,DAYOFWEEK(DATE(N_DAY))  WK
  FROM  (
    SELECT  DAYS(DATE('2007' || '-01-01')) +
            DG_1 + DG_2 + DG_3  N_DAY
      FROM
       (SELECT   0 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   1 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   2 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   3 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   4 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   5 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   6 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   7 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   8 DG_1 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT   9 DG_1 FROM SYSIBM.SYSDUMMY1) D1
      ,(SELECT   0 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  10 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  20 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  30 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  40 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  50 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  60 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  70 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  80 DG_2 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT  90 DG_2 FROM SYSIBM.SYSDUMMY1) D2
      ,(SELECT   0 DG_3 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT 100 DG_3 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT 200 DG_3 FROM SYSIBM.SYSDUMMY1 UNION ALL
        SELECT 300 DG_3 FROM SYSIBM.SYSDUMMY1) D3
     ) SEQ_0_399
 WHERE  N_DAY <= DAYS(DATE('2007' || '-12-31'))
   AND  DAYOFWEEK(DATE(N_DAY)) IN (1,7)
ORDER BY  DT

or

UDB(WIN,UNIX) 에서는

SELECT  DATE(N_DAY)             DT
       ,DAYOFWEEK(DATE(N_DAY))  WK
  FROM  (
    SELECT  DAYS(DATE('2007' || '-01-01')) +
            DG_1 + DG_2 + DG_3  N_DAY
      FROM  TABLE (VALUES 0,1,2,3,4,5,6,7,8,9)          T1 (DG_1)
           ,TABLE (VALUES 0,10,20,30,40,50,60,70,80,90) T2 (DG_2)
           ,TABLE (VALUES 0,100,200,300)                T3 (DG_3)
     ) SEQ_0_399
 WHERE  N_DAY <= DAYS(DATE('2007' || '-12-31'))
   AND  DAYOFWEEK(DATE(N_DAY)) IN (1,7)
ORDER BY  DT

이렇게 하면 되는군요. 아직 쿼리가 다 이해되지는 않지만(^^;) 원하는 결과가 나와 기쁩니다.
고맙습니다. 꾸벅