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;