WITH T
     AS (SELECT 6 AS NUM1, 3 AS NUM2 FROM DUAL
         UNION ALL
         SELECT 6 AS NUM1, 3 AS NUM2 FROM DUAL
         UNION ALL
         SELECT 1 AS NUM1, 6 AS NUM2 FROM DUAL
         UNION ALL
         SELECT 3 AS NUM1, 6 AS NUM2 FROM DUAL
         UNION ALL
         SELECT 3 AS NUM1, 6 AS NUM2 FROM DUAL
         UNION ALL
         SELECT 6 AS NUM1, 3 AS NUM2 FROM DUAL),
     cnt_t
     AS (  SELECT T1.NUM1, T1.NUM2, COUNT (*) AS cnt
             FROM T T1
         GROUP BY T1.NUM1, T1.NUM2),
     piv_t2
     AS (  SELECT *
             FROM cnt_t PIVOT (SUM (cnt) FOR NUM1 IN (1, 3, 6))
         ORDER BY NUM2),
     piv_t1
     AS (  SELECT *
             FROM cnt_t PIVOT (SUM (cnt) FOR NUM2 IN (1, 3, 6))
         ORDER BY NUM1)
SELECT NUM1,
       NVL (piv_t1."3", 0) || ';' || NVL (piv_t2."3", 0) AS "3",
       NVL (piv_t1."6", 0) || ';' || NVL (piv_t2."6", 0) AS "6",
       NVL (piv_t1."1", 0) || ';' || NVL (piv_t2."1", 0) AS "1"
  FROM piv_t1 FULL OUTER JOIN piv_t2 ON NUM1 = NUM2