oracle case when

select a.*,
       case
         when a.type = 'executeUnit' then 
          (select e.name from diqm_quality_executeunit e where e.id = a.reference) 
         when a.type = 'analyzer' then 
          (select e.name from diqm_quality_analyzer e where e.id = a.reference) 
          else    
          ''
          end name
     
from diqm_quality_analyzerrelation a