Oracle SQL Case when not able to combine

Question

We need to create a view that combines both these SQL statements together.

SELECT g.state_cd, g.state_name, 
    case when s.ROLE_ID = 110 then 'Yes' else 'No' end  POC
    FROM us_state g
    LEFT OUTER JOIN role s ON g.state_cd = s.OFC_STATE_CD
    and s.role_id = 110 


    SELECT g.state_cd, g.state_name, 
    case when s.ROLE_ID = 120 then 'Yes' else 'No' end  ADM
    FROM us_state g
    LEFT OUTER JOIN role s ON g.state_cd = s.OFC_STATE_CD
    and s.role_id = 120 

Eg.

An user will have multiple rows. Some users will have role = 110 & some users will have role = 120 & some will have a combination of both. So is it possible to create 1 SQL statement that combines both of these. The result should be:

MD Maryland Yes No
NY Newyork No Yes
NJ Newhersey Yes Yes

The above table implies:

MD user has only role of 110
NY user has only the role of 120
NJ user has both roles.

Hope I'm clear on what is needed & it makes sense.

I tried to combine them like this:

SELECT g.state_cd, g.state_name, 
case when s.ROLE_ID = 110 then 'Yes' else 'No' end  POC,
case when s.ROLE_ID = 120 then 'Yes' else 'No' end  ADM
FROM us_state g
LEFT OUTER JOIN role s ON g.state_cd = s.OFC_STATE_CD
and s.role_id in (110, 120)

But this doesn't work and it returns duplicate rows. Not sure what I'm missing here. I would appreciate it greatly if someone can help.

Thanks

Harish

Answer 1

You need to aggregate the results:

SELECT g.state_cd, g.state_name, 
       max(case when s.ROLE_ID = 110 then 'Yes' else 'No' end) as POC,
       max(case when s.ROLE_ID = 120 then 'Yes' else 'No' end) as ADM
FROM us_state g LEFT OUTER JOIN
     role s ON g.state_cd = s.OFC_STATE_CD and s.role_id in (110, 120)
group by g.state_cd, g.state_name

It turns out that "Yes" and "No" work well with MAX.

Answer 2

This is also a variation:

select state_cd, state_name
       ,case when (select count(*) from role r1 
               where r1.ofc_state_cd = s.state_cd 
                 and r1.role_id = 110) > 0 then 'YES' else 'NO' 
         end as POC
       ,case when (select count(*) from role r2 
               where r2.ofc_state_cd = s.state_cd
                 and r2.role_id = 120) > 0 then 'YES' else 'NO' 
         end as ADM
from us_state s;

http://sqlfiddle.com/#!4/161e7/8