Question

so this is my table–

create table student
(
stu_id int,
s_name nvarchar(max),
s_subject nvarchar(max),
marks varchar(20)
)

and the values are

insert into student values(123,'pammy','English','88');
insert into student values(123,'pammy','Maths','56');
insert into student values(124,'watts','Biology','98');
insert into student values(125,'Tom','Physics','90');
insert into student values(125,'Tom','Computer','95');
insert into student values(125,'Tom','ED','75');

so what i have done is extracted data which occurred thrice. and then concatenated the string values using sys_connect_by_path.
My code is–

 select stu_id,s_name,
max(sys_connect_by_path(s_subject, ', ' )) s_subject,
max(sys_connect_by_path(marks, ', ' )) marks

    from (select stu_id,s_name,s_subject,marks, 
                    row_number() over 
                   (partition by stu_id order by s_subject) rn
             from student
               )
   start with rn = 1
    connect by prior rn = rn-1 and prior stu_id = stu_id
    group by stu_id,s_name
having stu_id in ( select stu_id 
                    from student
                    group by stu_id 
                    having count(stu_id) >3 )
  order by stu_id,s_name

output of my code is —

stu_id      s_name  s_subject              marks
125         Tom     ,Physics,Computer,ED,    ,90,95,75,

the code is working perfectly, but I am using comma as seprator, and i just want to get rid of comma at the start and at the end. in s_subject column.

what I wants is

stu_id s_name s_subject marks
125 Tom Physics,Computer,ED 90,95,75

I tried trim function, but i could not get success.
I can substr the sys connect by path if my data is fixed, but here data is not fixed.
So pls help..

Answer 1

SQL>  select stu_id
  2        , s_name
  3        , ltrim(max(sys_connect_by_path(s_subject, ', ' )),', ') s_subject
  4        , ltrim(max(sys_connect_by_path(marks, ', ' )),', ') marks
  5     from ( select stu_id
  6                 , s_name
  7                 , s_subject
  8                 , marks
  9                 , row_number() over (partition by stu_id order by s_subject) rn
 10              from student
 11          )
 12    where level >= 3
 13    start with rn = 1
 14  connect by prior rn = rn - 1
 15      and prior stu_id = stu_id
 16    group by stu_id
 17        , s_name
 18  /

    STU_ID S_NAME     S_SUBJECT                      MARKS
---------- ---------- ------------------------------ --------------------
       125 Tom        Computer, ED, Physics          95, 75, 90

1 row selected.

Regards,
Rob.

PS: Thanks and +1 for providing the create table statement and insert statements.