CASE statement logic

Question

Hi i'm trying to get the output based on the conditions
with T as
(select 100001 ID , 'SLNG' RATING ,  'AA-' RAT_SYBL , 1 TYPE  FROM DUAL UNION ALL
select 100001  ID , 'SLNG' RATING ,  'AA--' RAT_SYBL , 2 TYPE  FROM DUAL UNION ALL
select 100002 ID , 'SHRT' RATING ,  'AA+' RAT_SYBL , 1 TYPE  FROM DUAL UNION ALL
select 100002  ID , 'SHRT' RATING ,  'AA++' RAT_SYBL , 2 TYPE  FROM DUAL
SELECT DISTINCT  ID,RATING,CASE WHEN (RATING='SLNG')
                                         THEN   /*   rat_sybl of TYPE= 1 */
                                         when (rating='SHRT' )
                                         THEN  /* rat_sybl of TYPE= 2 */
                                         END AS SEL_RATING,TYPE
FROM T In the above query i'm trying to achive the RAT_SYBL based on TYPE Column
IF RATING='SLNG' THEN get the RAT_SYBL (if type=1)
Similarly
IF RATING='SHRT' THEN get the RAT_SYBL (fi type =2)
Thank you

Answer 1

Hi,
as far i can see it you want only the rows with a value in SEL_RATING.
with T as
(select 100001 ID , 'SLNG' RATING ,  'AA-' RAT_SYBL , 1 TYPE  FROM DUAL UNION ALL
select 100001  ID , 'SLNG' RATING ,  'AA--' RAT_SYBL , 2 TYPE  FROM DUAL UNION ALL
select 100002 ID , 'SHRT' RATING ,  'AA+' RAT_SYBL , 1 TYPE  FROM DUAL UNION ALL
select 100002  ID , 'SHRT' RATING ,  'AA++' RAT_SYBL , 2 TYPE  FROM DUAL
select id, rating, max(sel_rating)
from
(SELECT ID,RATING,CASE WHEN (RATING='SLNG' AND TYPE = 1)
                                           THEN  RAT_SYBL /*   rat_sybl of TYPE= 1 */
                                           when (rating='SHRT' and TYPE = 2 )
                                           THEN  RAT_SYBL/* rat_sybl of TYPE= 2 */
                                           END AS SEL_RATING,TYPE
   FROM T)
group by id, rating;