with t2 as(
select '1' god, '2' kod_sort, 'o' N1, 'o' N2, 'o' N3, 'o' N4, null N5, null N6, 'o' N7, 'o' N8, 'o' N9, 'o' N10, null N11 from dual union all
select '2' god, '2' kod_sort, null N1, 'o' N2, 'o' N3, 'o' N4, null N5, 'o' N6, 'o' N7, 'o' N8, 'o' N9, 'o' N10, null N11 from dual union all
select '3' god, '2' kod_sort, 'o' N1, 'o' N2, 'o' N3, 'o' N4, null N5, null N6, 'o' N7, 'o' N8, 'o' N9, null N10, null N11 from dual union all
select '4' god, '2' kod_sort, 'o' N1, null N2, 'o' N3, 'o' N4, null N5, null N6, 'o' N7, 'o' N8, 'o' N9, 'o' N10, null N11 from dual)

select God, Kod_Sort, listagg(lag_WN) within group (order by RN,kod_sort) vacation 
from (
select rownum RN, God, Kod_Sort,

case when lead(Week_Number) over(PARTITION by God order by Kod_Sort) - Week_number > 1 then Weeks||';'
     when lead(Week_Number) over(PARTITION by God order by Kod_Sort) is null then Weeks||';'
     when lag(Week_Number) over(PARTITION by God order by Kod_Sort) is null then Weeks||','
     when Week_number - lag(Week_Number) over(PARTITION by God order by Kod_Sort) > 1 then Weeks||','
     else null end lag_WN

         from (
                select God, Kod_Sort, weeks, Vacation, cast(ltrim(weeks,'N')as number) Week_Number from t2
                unpivot (vacation for weeks in (N1,N2,N3,N4,N5,N6,N7,N8,N9,N10,N11))
                order by God, Kod_Sort, cast(ltrim(weeks,'N')as number)
              )
     )
group by god, Kod_Sort



1              2              N1,N4;N7,N10;
2              2              N2,N4;N6,N10;
3              2              N1,N4;N7,N9;
4              2              N1;N3,N4;N7,N10;

create or replace FUNCTION week(i_code IN INTEGER, i_year in integer) RETURN VARCHAR2 IS
  l_list  VARCHAR2(32767);
  l_res   VARCHAR2(4000);
BEGIN
SELECT listagg('CASE WHEN '||column_name||' IN(''о'') THEN '|| to_char( trunc (to_date(i_year||'0101', 'yyyymmdd') 
+ ((LTRIM(column_name,'N'))-1)*7, 'ww'), 'dd.mm')||'||''; '' ELSE NULL END ' ,'||') 
WITHIN GROUP(ORDER BY 1)
  INTO  l_list
  FROM  user_tab_columns
  WHERE TABLE_NAME = 'GRAFIK' 
  AND column_name LIKE 'N%';
  EXECUTE IMMEDIATE 'SELECT '||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year' INTO l_res USING i_code,i_year;
  RETURN RTRIM(l_res);
END;

SELECT listagg(column_name||(LTRIM(column_name,'N'), ', ')
  FROM  user_tab_columns
  WHERE TABLE_NAME = 'GRAFIK' 
  AND column_name LIKE 'N%';

create or replace FUNCTION get_week_list1(i_code IN INTEGER, i_year in integer) RETURN VARCHAR2 IS
l_list VARCHAR2(32767);
l_res VARCHAR2(4000);
BEGIN
SELECT listagg('CASE WHEN '||column_name||' IN(''о'') THEN '|| to_char( trunc (to_date(i_year||'0101', 'yyyymmdd') 
+ ((LTRIM(column_name,'N'))-1)*7, 'ww'), 'dd.mm')||'||''; '' ELSE NULL END ' ,'||') -- здесь идёт динамический перебор 52 столбцов,
---причём я отделяю те, что с N от остальных (кода сотрудника и года) и одновременно преобразую их в дату (день и месяц недели)
--- также здесь идёт проверка и вытаскиваются те слобцы, что имеют значения о
WITHIN GROUP(ORDER BY 1)
INTO l_list
FROM user_tab_columns
WHERE TABLE_NAME = 'GRAFIK' 
AND column_name LIKE 'N%';
EXECUTE IMMEDIATE 'SELECT '||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year' INTO l_res USING i_code,i_year;
RETURN RTRIM(l_res);
END;

SELECT t.god, t.kod_sotr, regexp_substr (get_week_list1(t.kod_sotr,t.god), '^([[:digit:]]+)(,)([[:digit:]]+)(;)') as week_first, 
regexp_substr (get_week_list1(t.kod_sotr,t.god), '([[:digit:]]+)(,)([[:digit:]]+)(;)$') as week_last FROM GRAFIK t;

  1  create or replace FUNCTION
  2   get_week_list2(i_code IN INTEGER, i_year in integer)
  3  RETURN VARCHAR2 IS
  4   l_list VARCHAR2(32767);
  5   l_res VARCHAR2(4000);
  6  BEGIN
  7   SELECT listagg(column_name,',') WITHIN GROUP(ORDER BY to_number(LTRIM(column_name,'N')))
  8   INTO l_list
  9   FROM user_tab_columns
 10   WHERE TABLE_NAME = 'GRAFIK' AND column_name LIKE 'N%';
 11   l_list:='with t2 as(
 12   select God, Kod_sotr,'||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year)'||
 13  q'~
 14  select /* God, Kod_sotr, */ listagg(lag_WN) within group (order by RN,Kod_sotr) vacation
 15  from (
 16  select rownum RN, God, Kod_sotr,
 17  case when lead(Week_Number) over(PARTITION by God order by Kod_sotr) - Week_number > 1 then Weeks||';'
 18       when lead(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||';'
 19       when lag(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||','
 20       when Week_number - lag(Week_Number) over(PARTITION by God order by Kod_sotr) > 1 then Weeks||','
 21       else null end lag_WN
 22          from (
 23                  select God, Kod_sotr, weeks, Vacation, cast(ltrim(weeks,'N')as number) Week_Number from t2
 24                  unpivot (vacation for weeks in (~'||l_list||q'~))
 25                  order by God, Kod_sotr, cast(ltrim(weeks,'N')as number)
 26                )
 27          )group by god, Kod_sotr~';
 28  EXECUTE IMMEDIATE l_list INTO l_res USING i_code,i_year;
 29  RETURN RTRIM(l_res);
 30* END;
SQL> /

Function created.

SQL> select get_week_list2( kod_sotr,god) f,g.* from grafik g;

F                           GOD   KOD_SOTR N N N N N N N N N N
-------------------- ---------- ---------- - - - - - - - - - -
N1;N3,N8;N10;              2017        222 o   o o o o o o   o
N2,N8;N10;                 2017        202   o o o o o o o   o
N1;N3;N5;N7;N9;            2017        111 o   o   o   o   o


SQL> desc grafik
 Name                                      Null?    Type
 ----------------------------------------- -------- -------------
 GOD                                                NUMBER(38)
 KOD_SOTR                                           NUMBER(38)
 N1                                                 VARCHAR2(1)
 N2                                                 VARCHAR2(1)
 N3                                                 VARCHAR2(1)
 N4                                                 VARCHAR2(1)
 N5                                                 VARCHAR2(1)
 N6                                                 VARCHAR2(1)
 N7                                                 VARCHAR2(1)
 N8                                                 VARCHAR2(1)
 N9                                                 VARCHAR2(1)
 N10                                                VARCHAR2(1)

create or replace FUNCTION
 week_fun(i_code IN INTEGER, i_year in integer)
RETURN VARCHAR2 IS
l_list VARCHAR2(32767);
 l_res VARCHAR2(4000);
 BEGIN SELECT listagg(column_name,',') WITHIN GROUP(ORDER BY to_number(LTRIM(column_name,'N')))
 INTO l_list
 FROM user_tab_columns
 WHERE TABLE_NAME = 'GRAFIK' AND column_name LIKE 'N%';
   l_list:='with t2 as(
  select God, Kod_sotr,'||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year)'||
  q'~
 select /* God, Kod_sotr, */ listagg(lag_WN) within group (order by RN,Kod_sotr) vacation
  from (
  select rownum RN, God, Kod_sotr,
  case when lead(Week_Number) over(PARTITION by God order by Kod_sotr) - Week_number > 1 then Weeks||';'
      when lead(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||';'
       when lag(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||','
       when Week_number - lag(Week_Number) over(PARTITION by God order by Kod_sotr) > 1 then Weeks||','
       else null end lag_WN
          from (
                   select God, Kod_sotr, weeks, Vacation, cast(ltrim(weeks,'N')as number) Week_Number from t2
                  unpivot (vacation for weeks in (~'||l_list||q'~))
                 order by God, Kod_sotr, cast(ltrim(weeks,'N')as number)
                )where vacation='o'
          )group by god, Kod_sotr~';
   EXECUTE IMMEDIATE l_list INTO l_res USING i_code,i_year;
  RETURN RTRIM(l_res);
  END;

create or replace FUNCTION
 week_fun1(i_code IN INTEGER, i_year in integer)
RETURN VARCHAR2 IS
l_list VARCHAR2(32767);
 l_res VARCHAR2(4000);
 BEGIN SELECT listagg(column_name,',') WITHIN GROUP(ORDER BY to_number(LTRIM(column_name,'N')))
 INTO l_list
 FROM user_tab_columns
 WHERE TABLE_NAME = 'GRAFIK' AND column_name LIKE 'N%';
   l_list:='with t2 as(
  select God, Kod_sotr,'||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year)'||
  q'~
 select /* God, Kod_sotr, */ listagg(lag_WN) within group (order by RN,Kod_sotr) vacation
  from (
  select rownum RN, God, Kod_sotr,
  case when lead(Week_Number) over(PARTITION by God order by Kod_sotr) - Week_number > 1 then Weeks||';'
      when lead(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||';'
       when lag(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||','
       when Week_number - lag(Week_Number) over(PARTITION by God order by Kod_sotr) > 1 then Weeks||','
       else null end lag_WN
          from (
                   select God, Kod_sotr, weeks, Vacation, cast(to_char( trunc (to_date(~'||i_year||q'~||'0101', 'yyyymmdd') 
+ ((LTRIM(weeks,'N'))-1)*7, 'ww'), 'dd.mm')as number) Week_Number from t2
                  unpivot (vacation for weeks in (~'||l_list||q'~))
                 order by God, Kod_sotr, cast(to_char( trunc (to_date(~'||i_year||q'~||'0101', 'yyyymmdd') 
+ ((LTRIM(weeks,'N'))-1)*7, 'ww'), 'dd.mm')as number)
                )
          )group by god, Kod_sotr~';
   EXECUTE IMMEDIATE l_list INTO l_res USING i_code,i_year;
  RETURN RTRIM(l_res);
  END;

create or replace FUNCTION
 week_fun1(i_code IN INTEGER, i_year in integer)
RETURN VARCHAR2 IS
l_list VARCHAR2(32767);
 l_res VARCHAR2(4000);
 BEGIN SELECT listagg(column_name,',') WITHIN GROUP(ORDER BY to_char( trunc (to_date(i_year||'0101', 'yyyymmdd') 
+ ((LTRIM(column_name,'N'))-1)*7, 'ww'), 'dd.mm'))
 INTO l_list
 FROM user_tab_columns
 WHERE TABLE_NAME = 'GRAFIK' AND column_name LIKE 'N%';
   l_list:='with t2 as(
  select God, Kod_sotr,'||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year)'||
  q'~
 select /* God, Kod_sotr, */ listagg(lag_WN) within group (order by RN,Kod_sotr) vacation
  from (
  select rownum RN, God, Kod_sotr,
  case when lead(Week_Number) over(PARTITION by God order by Kod_sotr) - Week_number > 1 then Weeks||';'
      when lead(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||';'
       when lag(Week_Number) over(PARTITION by God order by Kod_sotr) is null then Weeks||','
       when Week_number - lag(Week_Number) over(PARTITION by God order by Kod_sotr) > 1 then Weeks||','
       else null end lag_WN
          from (
                   select God, Kod_sotr, weeks, Vacation, cast(ltrim(weeks,'N')as number) Week_Number from t2
                  unpivot (vacation for weeks in (~'||l_list||q'~))
                 order by God, Kod_sotr, cast(ltrim(weeks,'N')as number)
                )where vacation='о'
          )group by god, Kod_sotr~';
   EXECUTE IMMEDIATE l_list INTO l_res USING i_code,i_year;
  RETURN RTRIM(l_res);
  END;

create or replace FUNCTION
 week_fun1(i_code IN INTEGER, i_year in integer)
RETURN VARCHAR2 IS
l_list VARCHAR2(32767);
 l_res VARCHAR2(4000);
 BEGIN SELECT listagg(column_name,',') WITHIN GROUP(ORDER BY to_char( trunc (to_date(i_year||'0101', 'yyyymmdd') 
+ ((LTRIM(column_name,'N'))-1)*7, 'ww'), 'dd.mm'))
 INTO l_list
 FROM user_tab_columns
 WHERE TABLE_NAME = 'GRAFIK' AND column_name LIKE 'N%';
   l_list:='with t2 as(
  select God, Kod_sotr,'||l_list||' FROM GRAFIK WHERE kod_sotr=:A AND god=:year)'||
  q'~
 select /* God, Kod_sotr, */ listagg(lag_WN) within group (order by RN,Kod_sotr) vacation
  from (
  select rownum RN, God, Kod_sotr,
  case when lead(Week_Number) over(PARTITION by God order by Kod_sotr) - Week_number > 1 then /*Weeks*/Weeks_D||';'
      when lead(Week_Number) over(PARTITION by God order by Kod_sotr) is null then            /*Weeks*/Weeks_D||';'
       when lag(Week_Number) over(PARTITION by God order by Kod_sotr) is null then            /*Weeks*/Weeks_D||','
       when Week_number - lag(Week_Number) over(PARTITION by God order by Kod_sotr) > 1 then  /*Weeks*/Weeks_D||','
       else null end lag_WN
          from (
                   select God, Kod_sotr, /*weeks*/
to_char(trunc(to_date(god,'yyyy'),'y')+(cast(ltrim(weeks,'N') as number)-1)*7,'dd.mm') Weeks_D, 
                   Vacation, cast(ltrim(weeks,'N')as number) Week_Number from t2
                  unpivot (vacation for weeks in (~'||l_list||q'~))
                 order by God, Kod_sotr, cast(ltrim(weeks,'N')as number)
                )where vacation='о'
          )group by god, Kod_sotr~';
   EXECUTE IMMEDIATE l_list INTO l_res USING i_code,i_year;
  RETURN RTRIM(l_res);
  END;