Concatenate Multiple columns to one Row - Oracle 10.1

Question

Hi Friends,
I have the item id in the item table and list of warehouses in another table.
SDM_ITEM_TABLE
ITM_ID ITM_DESC
1 Baby Oil
2 Shampoo
SDM_OUTBOUND_LOG
ITM_ID WHS_ID
1 1
1 2
1 3
1 4
2 1
2 2
SDM_OUTBOUND_DESC
WHS_ID WHS_SNAME
1 NJ
2 WN
3 CA
4 CN
Expected Result
ITM_ID WHS_SNAME
1 NJ WN CA CN
2 NJ WN
I am using the below query to join the above 3 tables , but i am unable to concatenate the warehouse short names as displayed above.
select t.itm_id,(SELECT H.WHS_SNAME FROM SDM_OUTBOUND_DESC H WHERE H.WHS_ID = t.WHS_ID) WHS_SNAME
from SDM_OUTBOUND_LOG t, SDM_ITEM_TABLE i
where t.itm_id = i.itm_id
Please let me know how to proceed further in modifying the query to concatenate the warehouse names.
Thanks

Answer 1

Centinul gave you the links to many examples.
You should try them all and find out how they work and let us know what parts are not clear.
Not sure why you are joining all three tables here, it looks like the desired resultset can be selected using
sdm_outbound_log and sdm_outbound_desc only?
One way of concatenating column values, is to use SYS_CONNECT_BY_PATH (but there are many more).
The query below reads from 'inside-out':
SQL> create table sdm_outbound_log as
  2  select 1 itm_id, 1 whs_id from dual union
  3  select 1, 2 from dual union
  4  select 1, 3 from dual union
  5  select 1, 4 from dual union
  6  select 2, 1 from dual union
  7  select 2, 2 from dual;
Table created.
SQL> create table sdm_outbound_desc as
  2  select 1 whs_id, 'NJ' whs_sname from dual union
  3  select 2, 'WN' from dual union
  4  select 3, 'CA' from dual union
  5  select 4, 'CN' from dual;
Table created.
SQL> select itm_id
  2  ,      ltrim(replace( sys_connect_by_path(whs_sname, ',') 
  3                      , ',', chr(32)
  4                      )
  5              ) whs_sname
  6  from ( select l.itm_id
  7         ,      d.whs_sname
  8         ,      row_number() over (partition by l.itm_id order by l.itm_id) rn
  9         from   sdm_outbound_log l
10         ,      sdm_outbound_desc d
11         where  d.whs_id = l.whs_id
12       )
13  where connect_by_isleaf=1    
14  start with rn=1
15  connect by rn=prior rn+1    
16         and itm_id=prior itm_id;
    ITM_ID WHS_SNAME
         1 NJ WN CA CN
         2 NJ WN
2 rows selected.So, in the innermost query we start by using row_number() to obtain a rownumber within each occurence of itm_id,
and then we connect by that rownumber and itm_id in the outermost query.
Since it looks like you want your values delimited by a space, I added a replace and a ltrim.