CREATE TABLE Course
(
    S_No int,
    course nvarchar(25)     
)
 
INSERT Course
SELECT 1,'math 1'       UNION ALL
SELECT 1,'phisisc 1'    UNION ALL
SELECT 2,'math 1'       UNION ALL
SELECT 3,'culture'      UNION ALL
SELECT 3,'history'      UNION ALL
SELECT 3,'art'


S_No        course
----------- -------------------------
1           math 1
1           phisisc 1
2           math 1
3           culture
3           history
3           art

s_no        course 1                  course 2                  course 3
----------- ------------------------- ------------------------- ------------
1           math 1                    phisisc 1                 NULL
2           math 1                    NULL                      NULL
3           art                       culture                   history

-- #1
if object_id('temp') is not null drop table temp
SELECT  S_no,
          course,
          row=ROW_NUMBER() OVER(PARTITION BY S_no ORDER BY course)
          INTO temp
FROM Course 
 
SELECT  s_no,
          [course 1]=(SELECT course FROM temp t 
                      WHERE t.s_no=s.s_no AND t.row=1),
          [course 2]=(SELECT course FROM temp t 
                      WHERE t.s_no=s.s_no AND t.row=2),
          [course 3]=(SELECT course FROM temp t 
                      WHERE t.s_no=s.s_no AND t.row=3)
FROM (SELECT DISTINCT s_no
      FROM temp) s


-- #2
if object_id('temp') is not null drop table temp
SELECT  S_no,
          course,
          row=ROW_NUMBER() OVER(PARTITION BY S_no ORDER BY course)
          INTO temp
FROM Course 
  
SELECT  [Student Number]=(CASE  WHEN D1.S_no IS NOT NULL THEN D1.S_no 
                               ELSE 
                               CASE WHEN D2.S_no IS NOT NULL THEN D2.S_no
                                    ELSE D3.S_no 
                               END
                          END),
          D1.course,
          D2.course,
          D3.course
FROM
(
    SELECT  S_no,
                course                  
    FROM temp   
    WHERE row=1
) D1
FULL OUTER JOIN 
(
    SELECT  S_no,
                course            
    FROM temp
    where row=2
)D2 ON D1.s_no=D2.S_no
FULL OUTER JOIN
(
    SELECT  S_no,
                course            
    FROM temp
    WHERE row=3
)D3 ON D3.s_no=D2.S_no

select s_no,max(case when rid = 1 then course end) as course1,
max(case when rid = 2 then course end) as course2,
max(case when rid = 3 then course end) as course3
from (Select row_Number() over (partition by S_No order by course) as RID,*
from #Course) p
group by s_no

Warning: Null value is eliminated by an aggregate or other SET operation.