SELECT a,b
FROM 
(
  SELECT decode(col,1,rn) a,lead(decode(col,0,rn))over(ORDER BY 1) b
  FROM 
  (
    SELECT rn, MOD(rn,2) col
    FROM
    (SELECT ROWNUM rn FROM dual CONNECT BY ROWNUM<7)
    )
) WHERE a IS NOT NULL AND b IS NOT NULL

--2列的情况:
1    2
3    4
5    6

------解决方案--------------------

--创建环境
create table tmpTable as
with tmp as (
select 1 as col1 from dual
union  
select 2 from dual
union
select 3 from dual
union  
select 4 from dual
union  
select 5 from dual
union  
select 6 from dual
)
select * from tmp;

--创建存储过程
CREATE OR REPLACE PROCEDURE TEST_COL_TO_ROW
(
 colNum IN INT,
 user_cursor   out  sys_refcursor
 )
AS
  V_SQL VARCHAR2(8000);
  
  BEGIN
   V_SQL := 'SELECT ';
  
   FOR X IN 1..colNum LOOP
       V_SQL := V_SQL || 'SUM(DECODE(mod(rownum-1,'||to_char(colNum)||'),'||to_char(x-1)||',col1,0)) COL'||to_char(x) || ',' ;
    END LOOP;
   
  V_SQL := RTRIM(V_SQL,','); 
   V_SQL := V_SQL || ' from tmpTable group by trunc((rownum-1)/'||to_char(colNum)||') order by trunc((rownum-1)/'||to_char(colNum)||')';
  
   --DBMS_OUTPUT.PUT_LINE(V_SQL);
   OPEN user_cursor FOR V_SQL;  
   --EXECUTE IMMEDIATE V_SQL;
  
  END;


--SQLPLUS中执行

SQL> variable v_c refcursor;
SQL> exec TEST_COL_TO_ROW(2,:v_c);

PL/SQL 过程已成功完成。

SQL> print :v_c;

     COL1       COL2
---------- ----------
        1          2
        3          4
        5          6

SQL> variable v_c refcursor;
SQL> exec TEST_COL_TO_ROW(3,:v_c);

PL/SQL 过程已成功完成。

SQL> print :v_c;

     COL1       COL2       COL3
---------- ---------- ----------
        1          2          3
        4          5          6

------解决方案--------------------
select wm_concat(a) from tablet group by ceil(a/n)
n自己确定