For this sample data how to fulfill my requirement ?

Question

For this sample data how to fulfill my requirement ?
with temp as
select 'MON' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'III' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'II' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL
select ?? (what will be the query ??)
How can i get output data in this way :
WEEKDAY TIMING CLASS
MON 9-10 I,II,III
MON 10-11 I,II
TUE 9-10 I,II

Answer 1

If in 11g, you can use LISTAGG
with temp as
select 'MON' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'III' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'II' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL
select
WEEKDAY,
TIMING,
LISTAGG(CLASS,',') WITHIN GROUP (order by 1) as class_aggregate
from temp
GROUP by WEEKDAY,TIMING;
WEEKDAY       TIMING     CLASS_AGGREGATE
MON           9-10       I,II,III
MON           10-11      I,II
TUE           9-10       I,IIOther techniques for different versions are also mentioned here :
http://www.oracle-base.com/articles/misc/StringAggregationTechniques.php#listagg